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t T. E. PAGE, C.H., LITT.D. 

t E. CAPPS, ph.d., ll.d. f W. H. D. ROUSE, litt.d. 

L. A. POST, l.h.d. E. H. WARMINGTON, m.a., f.b.hjst.soc. 






A. L. PECK, M.A., Ph.D. 



F. H. A. MARSHALL, C.B.E., Sc.D., F.R.S. 










First printed 1937 
Revised and reprinted 1945, 1955 
Revised and reprinted 19G1 

Printed in Great Britain 

A r> ■ < J 

H > ocL 




Foreword ....... 3 

Introduction ...... 8 

Text and Translation .... 52 



Introduction ...... 436 

Text and Translation . . . . 440 

Index to Parts of Animals . . . 543 

Index to Movement and Progression of 

Animals. 552 


From quotations which I had seen, I had a high notion 
of Aristotle's merits, but I had not the most remote notion 
what a wonderful man he was. Linnaeus and Cuvier have 
been my two gods, though in very different ways, but they 
were mere schoolboys to old Aristotle. 

Charles Darwin to 
William Ogle, on 
the publication of 
his translation of 
The Parts of Ani- 
mals, 1882. 



A. E. P. and L. A. P. 


Aristotle refers to the De partibus animalium as an 
inquiry into the causes that in each ease have deter- 
mined the composition of animals. He does not, 
however, employ the category of causation in the 
manner normally adopted by men of scienee, since 
in this book causes are always considered in relation 
to ends or purposes, and design is regarded as having 
had a far larger share in the origin and development 
of living structures than that allotted to necessity. 

In the Historia animalium the parts themselves are 
described, for although this work is to some extent 
physiological, its main object was to deal with the 
anatomy of the organism. The De pariibus animalium, 
on the other hand, is almost exclusively physiological 
and teleological, and treats of the functions of the 
parts. But Aristotle's position was that of a teleo- 
logist only in a limited degree, for he appears to 
have taken that view of life which Bergson ealls the 
doctrine of internal finality (that is to say, that each 
individual, or at any rate eaeh species, is made for 
itself, that all its parts conspire for the greatest good 
of the whole, and are intelligently organized in view 
of that end but without regard for other organisms 
or kinds of organisms). Since every organ or part 
of the body was held to have its peculiar funetion, 
the existence of vestigial or rudimentary organs was 
a2 3 


unrecognized. This was the doctrine of internal 
finality which was generally accepted until Darwin 
elaborated his theory of Natural Selection. The 
wider doctrine of external finality, according to 
which living beings are ordered in regard to one 
another, never gained acceptance among scientific 
philosophers, and the only indication that Aristotle 
ever adopted it is furnished by a passage in which 
he suggests that the mouth in Selachians is placed 
on the under surface so as to allow their prey to 
escape while the fish are turning on their backs 
before taking their food ; but even this he qualified 
by the suggestion that the arrangement served a 
useful end for the fishes in question by preventing 
them from indulging in the harmful habit of gluttony. 

The De partibus animalium opens with an intro- 
duction devoted to general considerations. This is 
followed by a discussion of the three degrees of 
composition, the first degree being composition of 
physical substances, the second degree, of homo- 
geneous parts or tissues, and the third, of hetero- 
geneous parts or organs. The tissues referred to are 
blood, fat, marrow, brain, flesh, and bone. After 
describing these, the organs are dealt with, and a 
consideration of their respective functions, first in 
sanguineous animals (i.e. in Vertebrates), and secondly 
in bloodless animals (i.e. Invertebrates), occupies the 
remainder of the book. The account given of the 
physiology of the blood is especially interesting, and 
it is noteworthy that Aristotle understood something 
of the nature of the process of absorption whereby 
the food becomes converted into nutriment which is 
carried by the blood to all parts of the body. He 
supposed, however, that the matter derived from the 



gut passed first to the heart in the form of vapour 
or serum, and that it was there converted into true 
blood by a process of concoction. Aristotle knew 
nothing of the real nature of respiration, and he 
regarded the lungs as serving to temper the bodily 
heat by means of the inspired air. He was also 
entirely ignorant of the fact that the blood passes 
back to the heart and lungs after supplying the 
tissues and organs with nourishment. On the other 
hand, he fully appreciated the existence of exeretory 
organs, the function of which was to remove from the 
body such substances as could not be utilized. In 
this category are included fluids such as bile, urine, 
and sweat. In the seetion on the gall-bladder, as 
.in so many other passages in his works on natural 
history, it is truly remarkable how correct Aristotle 
is in his statements. He points out that the gall- 
bladder is not found either in the horse and ass or 
in the deer and roe, but is generally present in the 
sheep and goat. In the light of the knowledge that 
he possessed, therefore, Aristotle could scarcely have 
adopted a theory about this organ which has found 
expression in certain modern writings. According 
to this theory the gall-bladder is present in the sheep 
and ox because, these being ruminating animals, 
bile is only required at certain particular times when 
food passes into the intestine, whereas in the horse, 
which does not chew the cud, but yet is constantly 
eating, food is continually passing into the intestine 
and consequently a perpetual flow of bile is desirable. 
Since the gall-bladder is present in the non-ruminating 
pig but absent in the ruminating deer and roe, it 
is obvious that this theory cannot be consistently 



It is interesting to speculate about the school of 
research workers who must have contributed in 
providing material for this and the other works on 
natural science ascribed to Aristotle — who they were, 
the circumstances under which they lived, and what 
manner of facilities were available for their investiga- 
tions — for it would seem certain that no man single- 
handed could possibly have acquired such a vast body 
of knowledge, hardly any of which could have been 
derived from earlier observers. Yet the work in its 
completed whole seems to show the mark of one 
master hand, and its uniform character and the clear 
line of teleological reasoning that runs through it 
have been well brought out in Dr. Peck's translation. 
But putting aside its philosophical implications, the 
book consists of an attempt at a scientific record of 
all the apparently known facts relating to animal 
function. These are considered comparatively and 
as far as possible are brought into relation with one 
another. And thus, as the earliest text-book on 
animal physiology in the world's history, this treatise 
will ever make its appeal, not only to the classical 
philosopher, but to all who are interested in the origin 
and growth of biological science. 

F. H. A. M. 




Title. The traditional title of this treatise is not a very 
informative one. The subject of the work is, how- 
ever, stated quite clearly by Aristotle at the begin- 
ning of the second Book in these words : " I have 
already described with considerable detail in my 
Researches upon Animals what and how many are the 
parts of which animals are composed. We must now 
leave on one side what was said there, as our present 
task is to consider what are the causes through which 
each animal is'as I there described it " (646 a 7 foil.). 
The title ought therefore to be " Of the Causes of the 
Parts of Animals" and this is the title actually applied 
to it by Aristotle himself (at De gen. an. 782 a 21). a 
Even so, the word " parts " is misleading : it in- 
cludes not only what we call parts, such as limbs and 
organs, but also constituents such as blood and 
marrow.* Perhaps, therefore, no harm is done by 
leaving the accepted (and convenient) Latin title 

Zoological The De partibus, as well as the other treatises 
works " contained in this volume, forms a portion of Aris- 
totle's zoological works. The foundation of these is 
the Historia animalium, or Researches about Animals, 
in nine books (the tenth is generally held to be 

° For the meaning of Cause see note below, p. 24. 
b See note on " part " below, p. 28. 



spurious), in which observations are recorded, and 
consequent upon this are the treatises in which 
Aristotle puts forward theories founded upon these 

An animal is, according to Aristotle, a " concrete 
entity " made up of " matter " and " form." Hence, 
in the De partibus Aristotle treats of the causes on 
account of which the bodies — the " matter " — of 
animals are shaped and constructed as they are, in 
general ; in the De incessu he deals specially with 
the parts that subserve locomotion. In the De anima 
he proceeds to consider Soul — the " form " of an 
animal. In the remaining treatises, of which De 
inotu, included in this volume, is one, he deals with 
what he calls the functions " common to body and 
Soul," among which he includes sensation, memory, 
appetite, pleasure, pain, waking, sleeping, respira- 
tion, and so forth (see De sensu 436 a). The complete 
scheme is set out below : 

I. Record of observations. 

Hisioria animalium. 10 (9) books. 

II. Theory based upon observations. 

treating of the way in 
which the" matter" 

4 books 


De partibus 

De incessu 

1 book 

(b) De anima 

of animals is ar- 
ranged to subserve 
their various pur- 

(treating of the "form" 
of animals — the 




Parva 7? at ur alia — 

De motu ani- 

De generatione 

1 book 

5 books 

treating of the func- 
tions " common to 
body and Soul," and 
in particular of 
some special de- 
partments of ani- 
mal behaviour. 

The section (b) is necessary to the completeness of 
the scheme, but as it has given rise to a whole depart- 
ment of study, it is usually treated apart from the rest. 
Thus the main bulk of the zoological and biological 
works may be taken to consist of the three great 
treatises, Historia animalium, De partibus animalium, 
and De generatione animalium. It was these which, 
through translations made from the Arabic, were 
restored to the West by those who revived scientific 
studies at the beginning of the thirteenth century. 
Date of The late D'Arcy W. Thompson, in the prefatory 
™ m t£n.' note to his translation of H.A.* wrote : " I think it 
can be shown that Aristotle's natural history studies 
were carried on, or mainly carried on, in his middle 
age, between his two periods of residence at Athens," 
i.e. in the Troad, in Lesbos and in Macedonia, between 
the years 347 and 335 : and this view has recently 
received convincing support from Mr. H. D. P. Lee, b 
who bases his argument upon an examination of the 
place-names in H.A. This is opposed to the view 
which has been current for some years past, c that 
the zoological works belong to a late period in Aris- 
totle's life, and has important consequences for the 
reconstruction of Aristotle's philosophical develop- 

a The Works of Aristotle translated, vol. iv., Oxford, 1910. 

b C.Q. xlii. (1948), 61 ff. 
e See W. D. Ross, Aristotle, and W. W. Jaeger, Aristotle. 



mcnt, which cannot be dealt with here. It may, 
however, be remarked that, as Thompson said, it 
would follow that we might legitimately proceed to 
interpret Aristotle's more strictly philosophical work 
in the light of his work in natural history. But apart 
from these considerations, the great importance of 
the zoological works is that they represent the first 
attempt in Europe to observe and describe in a 
scientific way the individual living object. 

Throughout the De partibus Aristotle endeavours to Teleology, 
provide a Final Cause ° to explain the facts which 
he records — some purpose which they are supposed 
to answer ; and Causes of this sort are by far the 
most common in his treatise. His outlook is there- 
fore justly described as " teleological " ; but it is 
important not to read too much into this description. 
Aristotle is never tired of telling us that Nature makes 
nothing and does nothing *' without a purpose " ; 
but if we ask what that purpose is we may find that 
the answer is not quite what we had expected. 
Plato's notion of the " form " tended to divert his 
attention from individuals through a hierarchy of 
successive " forms " ; but for Aristotle " form " is 
not independent of matter : form must be embodied 
in some matter, that is, in individuals. Thus we find 
all through that Aristotle cannot long keep his eyes 
from the individual wherein the form is actually 
embodied, because it, after all, is the End, the 
crowning achievement of the efforts of the four 
Causes. This outlook controls the arrangement of 
Aristotle's treatise. Since all processes of production 
are determined by the nature of the product which 
is to result from them, it is the fully developed product 
which we must first make it our business to observe, 

° The four Causes are dealt with in a separate note, p. 24. 



and when we have discovered what are its actual 
characteristics we may then go on to work out its 
Causes and to examine the processes by which it was 

Synopsis I give a brief synopsis and a contents-summary 

Summit of the De P<*rtibus *. 

Introduction : Methods. 

Composition of Substances : Three modes : 

(1) The primary substances. 

(2) The " uniform " parts. 

(3) The " non-uniform " parts. 
Consideration of (1) Hot, cold, solid, fluid. 

(2) Uniform parts : (a) fluid, (b) solid. 

(3) Non-uniform parts, as follows : — 
External parts of animals. 

Internal parts of blooded animals. 
Internal parts of bloodless animals. 
External parts of bloodless animals. 
External parts of blooded animals (resumed). 
(a) Vivipara. (b) Ovipara. 


Book I. 

639 a 15 ch. 1 Introduction. On the Method of Natural 

Two questions propounded : 

(1) Are we to begin with the ultimate 
species and describe its characteristics, 
or with those that are common to 
many species ? 



639 b 8 (2) (Put in three ways) : 

(a) Are we to take first the phenomena, 
and then proceed to their Causes ? 

(b) Which is the primary Cause, the 
Final or the Efficient (Motive) ? 
(Answered immediately : The 
Final ; with a reference also to the 
influence of Necessity.) 

(c) Are we to discuss first the pro- 
cesses by which the animal is 
formed, or the characteristics of 
it in its completed state ? 

Answer to question (2). 

W T e must begin with the phenomena, 
then go on to the Causes, and the forma- 
tive processes — or, in other words, the 
Final Cause concerns us first and foremost. 
This differs from the practice of the early 
philosophers, who concerned themselves 
with the Material Cause, though some- 
times also with the Efficient (Motive) 
Cause. We must begin at the End, not 
at the beginning. 

640 b 17 Thus we must consider not merely the 

primary substances, but the " uniform " 
parts, which are made out of them, and 
also the " non-uniform " parts. In doing 
this, we shall be paying attention to the 
Formal Cause, which is more important 
than the Material Cause : the animal as 
a finished whole is more significant than 
the substances out of which it was made. 
640 b 30 But mere form or shape is not enough : 

" shaped matter " is not an animal. 
" Form " in its full and true sense involves 
" Soul " : " Soul " somehow is the 
animals Efficient and Final Cause. Act- 
ually, it is not Soul in its entirety, but 



some " portion " of Soul which fulfils this 

641 b 10 Thus the universe and the living objects 

in it are the products of something 
analogous to human art : they are con- 
trolled by a Final Cause, 

642 a 1 But Necessity also has its place in the 

uniterse — 

not (1) " absolute " necessity 
nor (2) " coercive " necessity 
but (3) " conditional " necessity. 
These two Causes, the Final Cause and 
Necessity, set the stage for our piece. 

642 b 5 ch. 2 Criticisms of dichotomy as a method of 

classification of animals. 
644 all ch. 4 The correct method of classification is by 

groups, such as Birds and Fishes. 

644 a 23 Answer to question (1). 

We must deal with groups, not species (e.g. 
Bird, not Crane), and where a species does 
not belong to a larger group, we must deal 
with species, not individuals (e.g. Man, 
not Socrates). 

644 b 21 ch. 5 An Exhortation to the study of animals. 

645 b 1 Final summary of the Method, combining 

answers to both the original questions : 

(1) First we discuss the attributes common 
to a group ; 

(2) Then we give the explanation of them. 

Book II. 

646 a 8 ch. 1 Purpose and outline of the Treatise : Our 
subject is the causes of the parts of 



646 a 13 Three modes of composition : 

(1) Out of the " elements " or dynameis 
(hot, cold, fluid, solid). 

(2) The uniform parts (bone, flesh, etc.). 

(3) The non-uniform parts (face, hand, 
etc.). ^ 

The relation of them to each other, and 
the way in which the Causes control this 

647 a 3 Parts may be divided into : 

(a) Instrumental parts (non-uniform). 

(b) Media of sensation (uniform). 

647 a 25 The faculty of sensation has its seat in the 

heart, which is thus uniform ; but it is 
also non-uniform, as it has to do with 

647 b 10 ch. 2 The uniform parts, generally. Variations 

occur in each of them, as is illustrated by 
the example of Blood. 

648 a 20 Resumption of the Three modes of com- 

position : 

649 b 9 (1) The primary substances : meaning of 

" hot," " cold," " solid," " fluid," with 
special reference to Blood. This merges 
into a discussion of 
(2) The Uniform parts. 

Blood. Fibres. Intelligence and sensi- 
tivity, and " temperament " generally. 

651 a 20 ch. 5 Lard and Suet (forms of Blood). 

651 b 20 ch. 6 Marrow (a form of Blood). 

652 a 24 ch. 7 The Brain. 

653 b 19 ch. 8 Flesh — the " part " par excellence — 

and its counterpart. 
Bones, and their counterparts, and 
parts similar to Bone, 
ch. 10 (3) The Non-uniform parts of animals. 

(This occupies the rest of the work.) 



655 b 28 


1 statement of the three organs 

indispensable to animals. 

656 a 14 

Head : 

Brain. Sense-organs. 

657 a 12 ch. 11 


657 a 25 ch. 13 

Eyes, etc. (ch. 14 : Eyelashes 
and digression on Hair). 

658 b 27 ch. 16 

Nostrils (esp. the Elephant's). 

659 b 20 


660 a 14 ch. 17 


Book III. 

661 a 34 ch. 1 


661 b 27 

(Note on "the more and less.") 

662 a 16 


ooZ a o4 


662 b 23 ch. 2 


664 a 13 ch. 3 

Neck : 


664 a 36 

Larynx and windpipe. 

664 b 20 


665 a 27 eh. 4 Internal Parts of Blooded Animals: 
Viscera : 

665 b 5 Heart. 

667 b 15 ch. 5 Blood-vessels (Great Blood-vessel and 

Aorta, and generally). 

668 b 33 eh. 6 Lung. 

669 b 13 ch. 7 (Why viscera are double, and other 

remarks.) Liver and Spleen. 

670 b 32 ch. 8 Bladder. 

671 a 26 ch. 9 Kidneys. 

672 b 8 ch. 10 Diaphragm. 

673 b 4 ch. 11 Membranes. 

673 b 12 ch. 12 Variations in the Viscera (Liver and 


674 a 9 ch. 14 Stomach and Intestines. 

675 b 29 Jejunum. 

676 a 7 eh. 15 Rennet. 

Book IV. 

676 a 23 ch. 1 General. Internal parts of Ovipara. 


676 b 16 ch. 2 Gall-bladder and Bile. 

677 b 15 ch. 3 Omentum. 
677 b 37 ch. 4 Mesentery. 

678 a 27 ch. 5 Internal Parts of Bloodless Animals 
(Insects, Testacea, Crustacea, Cephalo- 
pods). With special reference to the 
Sepia's " ink," and the Sea-urchin's 
" ova." 

681 a 10 Creatures intermediate between animals 

and plants. 

682 a 30 External Parts of Bloodless Animals : 

682 a 35 ch. 6 Of Insects. 

683 b 4 ch. 7 Of Testacea. 

683 b 25 ch. 8 Of Crustacea. 

684 b 7 ch. 9 Of Cephalopods. 

685 b 30 ch. 10 External Parts of Blooded Animals: 

(a) Vivipara, (b) Ovipara. 

(a) Vivipara : 

686 a 6 Head and Neck. 

686 a 24 Hands and Feet and relative propor- 

tion of limbs. Beginning from Man, 
whose position is upright, there is a 
gradation of declivity in the animals, 
continuing to the plants, which are 

687 a 2 Nature's habit in assignment of organs. 

The structure of the human hand, etc. 

688 a 12 Breast. 

689 a 4 Excretory organs. 

689 b 2 Rear parts. 

690 a 5 Hoofs, hucklebones, etc. 
690b 12 (b) Ovipara: 

690 b 18 (i) Serpents and Quadrupeds. 

692 b 4 (ii) Birds. 

695 b 2 (iii) Fishes. 



697 a 15 (c) Intermediate Creatures : 

Seals and Bats. 

697 b 27 Conclusion. 

Method of A glance at the summary will show clearly the 
Button. or der of subjects which Aristotle lays down in the 
first book to be followed in a treatise such as the 
one in which he is engaged. 

First, (A) to describe the parts of animals as they 

are observed to be ; and 
then, (B) to give an account of their causes, and 

their formative processes. 
Under (A) the order of preference is to be : first, 
the parts (1) common to all animals ; (2) 
where necessary, those common to a 
group of animals only ; and lastly, (3) in 
exceptional instances, those peculiar to a 
single species. 
Also, it will be seen how Aristotle works out this 
scheme in the three books which follow. Before 
considering that, however, we should notice that 
Aristotle has a great deal to say about the correct 
classification of animals — or rather, against the in- 
correct classification of them. Chiefly, he inveighs 
against the method of dichotomy ; and his chief 
objection to it is a simple and effective one — that it 
does not work. It forces us to assign to each species 
one distinguishing mark, and one only (642 b 21 — 
643 a 24). And it cuts off kindred species from each 
other on the strength of some quite subordinate 

° De partibus is concerned chiefly with the causes and less 
> with the processes. 



characteristic (642 b 10 foil.). The right method, 
says Aristotle, is to follow popular usage and divide 
the animals up into well-defined groups such as 
Birds and Fishes. a And this leads him to distinguish 
two stages of difference : 

(a) Cases in which the parts differ " by excess or 
defect " — as in different species of the same 
genus or group. 

(b) Cases in which the resemblance is merely one 
of analogy — as in different genera. 

Examples of (a) : differences of colour and shape ; 

many or few ; large or small ; 
smooth or rough ; e.g. soft and 
firm flesh, long and short bill, 
many or few feathers. 
(b) bone and fish-spine ; nail and 
hoof ; hand and claw ; scale and 

(Reff. for the above, De part. an. 644 a 11-b 15 ; Hist, 
an. 486 a 15-b 21. See also Gen. An. (Loeb), Introd.) 

The doctrine of differences of" excess and defect," "The mo™ 
or, as Aristotle also calls them, of " the more and and leS3, 
less," may usefully be compared with that which 
underlies the modern theory of Transformations, and 
the comparison of related forms. Indeed, Professor 
D'Arcy Thompson asserts that " it is precisely . . . 
this Aristotelian * excess and defect ' in the case 
of form which our co-ordinate method is especially 
adapted to analyse, and to reveal and demonstrate 
as the main cause of w hat (again in the Aristotelian 
sense) we term ' specific ' differences " {Growth and 

° And of course, into Blooded and Bloodless, though there 
are, as Aristotle points out, no popular names for these 



Form, p. 726;. The co-ordinates to which he refers 
are those of the Cartesian method, on which is based 
the theory of Transformations. By means of them 
it is possible to exhibit, say, the cannon-bones of the 
ox, the sheep, and the giraffe as strictly proportionate 
and successive deformations of one and the same form. 
These deformations can be either simple elongations, 
as in the instance just cited, or they may occur 
according to an oblique or a radial system of co- 
ordinates, etc. a In this way, differences of " excess 
and defe'ct " are reduced to the terminology of 
mathematics ; and it is especially interesting to 
notice this, as the phrase " excess and defect " itself 
had, in the Greek of Aristotle's time, a mathematical 
connexion. With it may be compared the well- 
known Platonic phrase, " the great and small." But 
this is not the place to enlarge upon such topics. 5 
ciassifica- To return to Aristotle's classification. We find 
U \&tS * na ^ ne implements his preliminary outline in the 
following way : 

I. First, he treats of the parts which are found in 
many different groups of animals, and also those 
wlrich are to be considered counterparts of each 
other in different groups. This corresponds to 
A (1) above. 

II. As he proceeds with this, he comes to the 
Viscera, which occur only in blooded animals." 
This provides a convenient point for embarking 
upon his second main division — corresponding 

° For details see D'Arcy Thompson, op. cit. ch. xvii. 

6 The reader is referred to A. E. Taylor, " Forms and 
Numbers," in Mind, xxxv. 4-19 foil. ; xxxvi. 12 foil. ; D'Arcy 
Thompson, " Excess and Defect," in Mind, xxxviii. 43 foil. 

e By » viscera " Ar. means the blood-like ones only. 



to A (2) above — the parts common to a group 

of animals, and we have first : 

The Internal Parts of Blooded Animals. 

III. This is followed by — 

The Internal Parts of Bloodless Animals. Then, 

IV. The External Paris of Bloodless Animals. Then, 
V. The External Parts of Blooded Animals, 

which includes — ■ 

(a) Vivipara. 

(b) Ovipara. 

(i) Serpents and Quadrupeds. 

(ii) Birds. 

(iii) Fishes. 

(c) Intermediate Creatures. 

References to exceptional instances, as to Man, 
corresponding to the division A (3) above, are of 
course to be found throughout the work. 

Aristotle thus works out the main lines of his 
classification. And in each instance, where possible, 
he endeavours to assign the Cause, to name the 
purpose, which is responsible for the parts as he 
describes them. This corresponds to (B) above. 

And here Aristotle is forced to admit an apparent Necessity, 
addition to his scheme of Causes. The purpose, the 
good End, the final Cause, cannot always get a free 
hand. There is another Cause, Necessity. Aristotle 
takes great care to explain what is the nature of this 
Necessity (642 a 2 foil.). It is what he calls Necessity 
" ex hypothesis or " conditional " Necessity, the sort 
of Necessity which is implied by any final Cause 
being what it is. If a piece of wood is to be split 
by an axe, the axe must ex hypothesi be hard and 
sharp, and that necessitates the use of bronze or 



iron in the making of it. The same sort of Necessity 
applies in the works of Nature, for the living body 
itself is an instrument. It is thus the final Cause 
which necessitates the various stages of the process 
of formation and the use of such and such material. 

Another kind of Necessity, however, makes its 
appearance in Natural objects, and that is " simple " 
Necessity. The mere presence of certain things in 
a living organism entails of necessity the presence of 
others (see 645 b 32, 677 a 17, b 22). Some results 
follow inevitably from the very nature of the material 
used. This " simple " Necessity can therefore be 
regarded as a reassertion of themselves by the 
motive and material Causes a as against the final 
Cause. Sometimes, however, even in circumstances 
where " simple " Necessity operates, Nature is able to 
use the resulting products to subserve a final Cause 
(663 b 22, 32, 677 a 15 ; see also the note on Residues, 
p. 32). Cf. Gen. An. (Loeb), Introd. §§ 6-9. 
Scheme of The following table will show at a glance the 
" scheme of Animals as treated of by Aristotle in the 
De partibus : 

A. Blooded Animals 

B. Bloodless Animals 



Viviparous quadrupeds 


Oviparous quadrupeds 


and footless animals 
(reptiles and amphi- 





• See De gen. an. 778 b 1. 



between the above classes 

between land and water 


between quadrupeds and 


Note on the Four Classes of Bloodless Animals. — 
These, in order of increasing softness, as noted 
above, are the following (I give the Greek term, its 
literal translation, and the term which I have used 
to translate it in this volume) : 

ra evro/ia insected animals Insects 

ra oaTpaKoStpua shell-skinned animals Testacea 

t<x fjbaXaKoorrpaKa soft-shelled animals Crustacea 

ra fiaXaKia softies Cephalopods 

In using " Testacea " to translate ra ocrrpaKoSepfxa 
(" the animals with earthenware skins "), I use 
it in the old-fashioned sense, so as to include a 
number of shelled invertebrates, comprising Gastero- 
pods, Lamellibranchs, and some Echinoderms. It 
does not refer to the Testacea of modern zoologists, 
by whom the term is applied to the Foraminifera 
which are shelled Protozoa. The word " Ostraco- 
derms " (a transliteration of Aristotle's word) is now 
given by zoologists to a group of primitive fossil 



between animals and 




Technical The following notes on some of the more difficult 
terms. an( ^ i m p or tant of the technical terms used by Aristotle 
in the De partibus will, I hope, help to explain my 
translation and also to give some indication of the 
background of Aristotle's thought. (A fuller account 
will be found in De Gen. An., Loeb edn.) 

Atria, " cause." 

I retain the traditional translation " cause," 
although perhaps in some contexts " reason " may 
be a closer rendering, but a variation in the English 
term might well produce more confusion than clarity. 
To know, says Aristotle, is to know by means of 
Causes (see Anal. post. 9-i a 20). A thing is explained 
when you know its Causes. And a Cause is that 
which is responsible, in any of four senses, for a 
thing's existence. The four Causes, of which two 
are mentioned very near the beginning of the first 
book (639 b 11), are : 

(1) The Final Cause, the End or Object towards 
which a formative process advances, and for the 
sake of jvhich it advances — the logos, the rational 

(2) The Motive (or Efficient) Cause, the agent which 
is responsible for having set the process in motion ; 
it is that by which the thing is made. 

(3) The Formal Cause, or Form, which is responsible 
for the character of the course which the process 
follows (this also is described as the logos, ex- 
pressing rrhat the thing is). 

(4) The Material Cause, or Matter, out of which the 
thing is made. 



It will be seen that the first three Causes tend 
naturally to coalesce under the aegis of the Formal 
Cause, in opposition to the fourth, the Material 
Cause, a contrast which is clearly put by Adam of 
St. Victor in one of his hymns : 

Hence, of course, comes the regular contrast of 
" form " and " matter," in which, oddly enough, in 
modern usage the two terms have almost exchanged 
meanings. " Mere form," " empty form," in con- 
trast with " the real matter," are phrases which 
indicate a point of view very different from that of 
Aristotle. An equally drastic reversal of meaning 
has overtaken the term " substance," as contro- 
versies on " transubstantiation," and the existence 
of the word " unsubstantial " prove. " Cause " has 
certainly been more fortunate ; but its meaning has 
been narrowed down, so that " cause " now usually 
suggests the " efficient " cause only. At the same 
time, we allow ourselves a wider variety of " efficient " 
causes than Aristotle, and are more ready to admit 
actions and events or even series of actions and events. 
We have, in fact, applied Aristotle's precise termin- 
ology to the wider uses of everyday non-technical 
purposes. For Aristotle, the doctrine of the Four 
Causes provides an exhaustive and precise classifica- 
tion of the things which can be responsible for another 
thing's existence, and by the naming of them the 
thing can be completely accounted for. 

As an illustration the following will serve. 
Suppose the object to be explained is an oak. The 

causa Dens, etjinalis, 
sed numquam materia. 



chronological order of the Causes is different from 
their logical one. 

(i.) The Motive Cause : the parent oak which 
produced the acorn. 

(ii.) The Material Cause : the acorn and its nour- 

(iii.) The Formal Cause. The acorn as it grew 
into a tree followed a process of development 
which had the definite character proper to 

(iv.) The Final Cause : the end towards which 
the process advanced, the perfected oak-tree. 


There are several places in the De partibus where, 
rather than represent Adyo? by an inadequate or 
misleading word, I have transliterated it by logos* 
This serves the very useful purpose of reminding the 
reader that here is a term of very varied meanings, 
a term which brings into mind a number of correlated 
conceptions, of which one or another may be upper- 
most in a particular case. It is an assistance if we 
bear in mind that underlying the verb Aiyetr, as it 
is most frequently used, is the conception of rational 
utterance or expression, and the same is to be found 
with Aoyos, the noun derived from the same root. 
Aoyo? can signify, simply, something spoken or uttered ; 
or, with more prominence given to the rationality of 
the utterance, it can signify a rational explanation, 
expressive of a thing's nature, of the plan of it ; and 
from this come the further meanings of principle, or 
law, and also of definition, or formula, as expressing 


the structure or character of the object defined. 
(Note here the application of the term logos to the 
Final and Formal Causes, recorded in the foregoing 
note.) Another common meaning is seen especially 
in the use of the dative Aoyoj (cf. the verb Xoyt^ofiai 
and its noun) — by reason'mg, in thought, as opposed to 
fact or action. (See 640 a 32, Art is the Aoyo? rov 
epyov 6 avev tt}s vh)$ ; at 616 b 2 we read of the 
Aoyos of a process of formation sueh as building, and 
the Aoyos of the house which is built ; at 67S a 35 
of the A.dyos which defines the essence of something, 
and at 695 b 19 of " the /Yoyos of the essence," At 
639 b 15 the " Cause for the sake of which " — the 
Final Cause — is described as being a /Yoyos.) 

reVecris, " formation," or " proeess of formation." 
TtyvecrOaLy " to be formed," " to go through a proeess 
of formation." 

These are the translations which I normally use, 
as more appropriate in a biologieal treatise than 
" coming into being," and the like. 

The proeess of formation is of course closely con- 
nected in Aristotle's thought with the doctrine of the 
Four Causes. 

r^vecrts is a process which, at any rate in biology, 
results in the production of an actual object, a living 

Tevecrts is also contrasted with ovala and <£t'o-is a : the 
order of things, we are told, in the process of formation 
is the reverse of the order in reality. For example, 
the bricks and mortar exist for the sake of the house 

° Care should be taken not to regard (frvacs as meaning 
' the process of <f>ve.odai" 

B 27 


which is to be built out of them, but they and not it 
come first in the order of time and fact. Aristotle 
sums this up by saying that what comes last in the 
process comes first in 11 nature " (646 a 25). 

Mopiov, " part." 

The term which occurs in the title of the treatise 
and is traditionally rendered " part " includes more 
than is normally included in the English " part of 
the body." For instance, this would not normally 
be applied to blood, but the term jjLopiov is applied 
by Aristotle to all the constituent substances of the 
body as well as to the limbs and organs. For him, 
blood is one of the foW popia (648 a 2 ; see also 
664 a 9> 690 a 8). A striking instance of the use of 
fAopiov in this sense is the phrase ra bpow^pq ju,o/na, 
which are the subject of the next following note. 

Tot ojiotojjLeprj fiopca, " the uniform parts." 

Ta dvofjioiojjLepTj fiopio., " the non-uniform parts." 

Aristotle's application of the term popiov to both 
these classes emphasizes the inclusiveness of its 
meaning. As examples of the " uniform " parts he 
mentions (647 b 10) blood, serum, lard, suet, marrow, 
semen, bile, milk, flesh — these are soft and fluid 
ones ; also bone, fish-spine, sinew, blood-vessel — 
these are hard and solid ones. Of " non-uniform " 
parts he gives as examples (640 b 20) face, hand, foot. 

The relation of the " uniform " parts to the " non- 
uniform " he describes as follows (647 b 22 foil.) : 

° For the meaning of " fluid " and " solid " see below, 
p. 32. 


(a) some of the uniform are the material out of 
which the non-uniform are made (i.e. each 
instrumental part is made out of bones, sinews, 
flesh, etc.) ; 

(b) some act as the nutriment of (a) ; 

(c) some are the residue of (b) — faeces, urine. 

It is not possible to equate the two classes with the 
later division into tissues and organs, since blood, 
for instance, though " uniform," is not a tissue ; the 
term " organs," however, corresponds closely with 
Aristotle's own description — to. opyavtKa fxeprj 
(647 b 23), " instrumental parts." 

The practical difference between the two classes 
is that each of the uniform parts has its own definite 
character as a substance (in the modern sense), while 
each of the non-uniform parts has its own definite 
character as a conformation or organ. The heart is 
the only part which belongs to both classes (647 a 25 
foil.) : it consists of one uniform part only, namely, 
flesh ; but it also has essentially a definite configura- 
tion, and thus it is a non-uniform part. 

Three stages or " degrees of composition," so far 
as biology is concerned, are enumerated by Aristotle 
(at 646 a 13 foil.). What Aristotle seems to mean, 
though he has not expressed himself quite clearly, 
is that there are three stages involved in the com- 
position of compound bodies, namely, 

(1) the Wa/xeis (see following note) ; 

(2) the uniform parts ; 

(3) the non-uniform parts ; 

and finally, of course, out of the non-uniform parts 

(4) the animal itself is composed. 



We have thus : 

(1) the simplest sorts of matter ; 

(2) the simplest organic substances compounded 
out of the foregoing (having no definite size, 
shape, or structure) ; 

(3) the instrumental parts of the body constructed 
out of the foregoing (having definite size, shape, 
and structure) ; and 

(4) the organism as a -whole, assembled out of the 

Note. — For a description of the way in -which the 
term ra opoiojitprj has caused confusion in the accounts 
of Anaxagoras's theories see Class. Qu., 1931, xxv. 34 

This is one of the most difficult terms to render in 

The specialized meaning of Swa/iei, " potenti- 
ally," as opposed to ivtpyda, " actually," is so well 
known that there is no need to enlarge upon it here. 
Nor need I discuss the mathematical meaning of 
Suva/ns. Other meanings need some comment. 

(1) Auva/xts was the old technical term for what 
were later to be called o-roixeFa (elements). It 
appears in the writings of the Hippocratic corpus 
and in Plato's Timaeus. The best example of its 
use in De partibus is at the beginning of Book II. 
(646 a 15). The list of Swdptts included the sub- 
stances known as to vypov, to £i]poi' 9 to 6epp.6v } to 
\pv\pov, to TriKpnv, to yXvKv, to Spipv, etc., etc. Only 
the first four of these were regarded by Aristotle as 


the material of compound bodies : all the " other 
differences," he says, are consequent upon these. 

The original meaning underlying this usage of the 
term seems to have been " strong substance of a 
particular character." This would be very appro- 
priate to to Spifxvy to TrtKpov, etc. (see Uepl apx at7 7? 
hjTpiKrjs). There is no notion here of the substance 
havi?ig power in the sense of power to affect an 
external body in a particular way. (This meaning 
developed later.) If any effect did result, it would 
be described simply as the presence of the strong 
substance, and the remedy for it was to " concoct " 
the strong substance or otherwise to bring it into 
a harmless condition by " blending " it with other 

(2) As each of the substances known as Swdptis 
has its own peculiar character, sharply marked off 
from the others, the meaning of *' peculiar and dis- 
tinctive character " was naturally associated with the 
term. This seems to be its meaning in 655 b 12 : 
e£ dray /07s 8e ravra 7rarra y€0)8r] #cat wrtpeav l^ct tyjv 
<f>v(Ti\" ottXov yap avnj Indeed, in this mean- 
ing, Svvafjii seems to be a slightly more emphatic 
version of <£i»cn?, with which it is often used in con- 
junction (in Hippocrates, for instance), or in a parallel 
way as in the passage just cited. Compare also 
651 b 21, where the marrow is asserted to be at'/xaros 
T15 (j>vo- is, not, as some suppose, r?js yovrjs o-ircpfiaTiicf} 
SvvafjLis. Other instances of this use of Svvafiis wall 
be found in De partibus. 

(3) From this usage it is not far to the idiomatic, 
pleonastic usage, e.g. : 

678 a 13 ?/ tQv ivrkpwv Suva/its almost = ra evrtpa. 
682 b 15 rj twv irTtpwv Bvyatits. 



657 a 4 7} twv fivKrrjpwv SlW/xis Sk^vjJs. 
This is paralleled by a similar usage of <j>vo-i$ l 
663 a 34 17 Ttoi/ Kepdrmv </>i'o~ts. 

676 b 1 1 TtOV (j)V<TLS. 

(Other references for owa/us : 640 a 24, 646 a 14, 
b 17, 650 a 5, 651 b 21, 652 b 8, 12, 653 a 2, 655 b 12, 
658 b 34. See further Gen. A?i. } Loeb edn., Introd. 
§§ 23 if.). 

To vypov Kal to fypov, " fluid substance and solid 
substance," " the fluid and the solid." 

These are two of the Sura/iets. 

Following Ogle, I use these renderings as being 
more in conformity with the definitions given by 
Aristotle than " the moist and the dry," which have 
often been used. Actually neither pair of English 
words quite expresses the Greek. Aristotle's de- 
finition of them (at De gen. et corr. 329 b 30) is this : 

" vypov is that which is not limited by any limit of 
its own but can be readily limited, £i)p6v is that 
which is readily limited by a limit of its own but can 
with difficulty be limited " — i.e. of course by a limit 
imposed from without. 

He discusses the various senses in which these 
terms are used at 649 b 9 following. 

Ile/HTTto/xa, " residue." 

This term I have translated throughout " residue," 



as being more literal and at the same time less mis- 
leading than " excrement/' " Surplus " would have 
been even better if the word had been a little more 

" Residue " is so called because it is that which is 
left over when the living organism, by acting upon 
the nutriment which it has taken, has provided itself 
with a sufficient supply for its upkeep. Some of the 
surplus will be useless material contained in the food 
from the outset, or else has been produced during 
the process of reducing the food into a condition 
suitable for its purposes in the body. The useless 
residues include the excrements. In order to appreci- 
ate the status of the useful residues the outlines of 
the processes through which the food passes must be 
kept clearly in mind. Briefly, then, the food is 
masticated in the mouth, then passed on to the 
stomach and then the heart, where it is concocted a 
by means of heat — in other words, it is turned into 
blood, which is the " ultimate nourishment " ; and 
this, when distributed into the blood-vessels, supplies 
the body with nutrition. Generally, however, more 
blood is produced than is necessary for the actual 
upkeep of the body, and this surplus undergoes a 
further stage of concoction, and is used by Nature 
in various ways. Marrow is a residue ; so are semen, 
catamenia, milk. Sometimes, when nutrition is 
specially abundant, the surplus blood is concocted 
into fat (lard and suet). And some of the blood, 
reaching the extremities of the vessels in which it 
travels, makes its way out in the form of nails, claws, 
or hair. The Aristotelian doctrine of residues came 
down to Shakespeare, as is shown by the passage 

See page 34. 



in Hamlet (in. iv.) where the Queen says to Hamlet : 

Your bedded haire, like life in excrements, 
Start up, and stand an end. 

This theory, as applied to hair, is expounded by 
Aristotle at 65Sb 14- following, and modern biochemists 
have reason for believing that some pigmentation in 
animals, such as the black melanin of mammalian 
hair, or the yellow xanthopterine of the butterfly 's 
Ming, is physiologically a form of excretion. 

" Concoct" " concoction." 

These terms, which have already appeared in 
these notes, are used to translate irtororeiv, irkxpis. The 
Greek words are the same as those employed to 
denote the process of ripening or maturing of fruit, 
corn, and the like by means of heat — also that of 
baking and cooking. 

Terms sometimes associated with these are fxeraf3oXrj 
and (X€.raf3dXXeiv. For example, at 650 a 5 we read 
that Treats and j-uraf^oXi) take place <5ta r>}s tov Oepfiov 
8vvdfjL€<i)<s ; and at 651 b 26, as the creatures grow 
and get " matured," the parts jierajSaXXet their 
colour, and so do the viscera. 

^PV^j " Soul." 

The English word " Soul," as will be seen, over- 
emphasizes, when compared with i^>x 7 5> certain 
aspects of the Greek term, but it is by far the most 
convenient rendering, and I have used it in pre- 
ference to " life " or " vital principle." 

It will be useful to have an outline of Aristotle's 
general doctrine about Soul. 

The different " parts " or " faculties " of Soul can 



be arranged in a series in a definite order, so that the 
possession of any one of them implies the possession 
of all those which precede it in the list : 

(1) nutritive Soul in all plants 

At 641 a 23 Aristotle speaks of " parts " of the 
Soul, and though he often uses this phrase, the 
description he prefers is " faculties." In the passage 
which follows (Gil a 33 foil.) all except appetitive 
Soul are mentioned. Sentient Soul is mentioned 
again at 650 b 24, 667 b 23, 672 b 16. 

Aristotle raises the question whether it is the 
business of Natural science to deal with Soul in its 
entirety, and concludes that it is not necessary, since 
man is the only animal in which rational Soul is 
found. Thus it is only some part or parts of Soul, 
and not Soul in its entirety, which constitute animal 

In the passage 641 a 14 following, Aristotle takes 
for granted his doctrine about Soul, which is as 
follows (De anima, Book II.). Animate bodies, bodies 
" with Soul in them " (e/x^i-ya), are " concrete sub- 
stances " made up of matter and form. In this 
partnership, of course, the body is the matter and the 
Soul is the form. Thus Soul may be described as the 
" form " or " realization " (evTeAiyeiu, " actuality ") 
of the animal (cf. De part., loc. cit.). 

This statement, however, is elsewhere made more 
precise. It is possible to distinguish two " realiza- 
tions " of an animal ; for an animal " has Soul in it " 

(2) sentient Soul j 

(3) appetitive Soul ^ 

(4) locomotive Soul J 

(5) rational Soul i 

in man only 

in all animals 

in some animals 



even when it is asleep, but its full activity is not 
evident until it is awake and about its business. We 
must call Soul j then, the " first realization " of the 
animal, its waking life its " second realization." 
This distinction does not concern us in the De partibus. 
But an expansion of the definition is not irrelevant. 
Aristotle states that the Soul is the first realization 
of a body furnished with organs. The priority of 
Soul over body is emphasized in the passage just 
referred to (640 b 23—641 a 32), and in another in- 
teresting passage (6S7 a 8 foil.) Aristotle maintains 
that man has hands because he is the most intelli- 
gent animal, and not, as some have said, the most 
intelligent animal because he has hands. 

With this is connected the question whether the 
Soul is independent of the body ; though it is not 
raised in De partibus. As we have seen already, a 
froov is a single concrete entity made up of Soul and 
body, i.e. a certain form implanted in certain matter. 
The matter can exist, for it did exist, apart from the 
form ; and as the form that is implanted in all the 
individuals of a species is one and the same form, 
clearly it can exist apart from any one individual's 
matter — though of course its existence is not in- 
dependent of all the individuals' matter. Further- 
more, the form — the Soul — requires matter of a 
particular kind : not any sort of matter will do. 
From these considerations two conclusions seem to 
follow : (1) that transmigration is impossible : a 
human Soul cannot function in a hyena's body, any 
more than the carpenter's art can be executed by 
means of musical instruments ; (2) the Soul cannot 
function without a body at all ; cannot, we may say, 
exist (414 a 19). 



So far, so good. But Aristotle is not satisfied. 
He feels the Soul is more than that. He finds a 
loophole. There may be some " part " of Soul (the 
rational part) which is not the " realization " of any 
body. The Soul, besides being the form, the formal 
Cause, of the body, is also its final Cause, and not 
only that, but the motive Cause too of all the changes 
originated in the body (De anima 415 b 7-28), for, as 
we saw (p. 25), the three non-material Causes tend 
to coalesce into one. This independent " part " of 
Soul *' comes into the body from without " (see De 
gen. an. 736 b 25 foil.) and continues to exist after 
the death of the body (see De anima 413 a 6, b 24 foil., 
430 a 22, etc.). All t this, however, raises problems 
not touched upon in De partibus ; indeed Aristotle 
himself offers no solution of them. 

I have indicated above, in the note on 8iW/«s, 
some of the older (Hippocratic) medical terminology 
of which traces are to be found in the De partibus. 
There is no room for an adequate discussion of such 
terms and theories, and the following bare references 
must suffice. 

In the Hippocratic treatise ITept Siatrrjs the theory 
is put forward that the human organism, body and 
Soul alike, is composed of fire and water (which 
really consist of " the hot," " the solid," " the cold," 
and '* the fluid ") — the function of fire being to cause 
motion, of water to provide nourishment. In ch. 35 
we have a list of the different varieties of Blend 
(Kprjo-ts, <rvyKpr]<TLs) of fire and water which may be 



found in the Soul in different individuals, and upon 
the Blend its health and sensitivity a depend. 

With these statements may be compared the 
following passages in De partibus : 

652 b 8 Some, says Aristotle, maintain that the 

Soul is flic ; but it is better to say 
that it subsists in some such material. 
" The hot " is indeed the most ser- 
viceable material for the functions 
which the Soul has to perform, and 
these include nourishing and causing 

647 b SO foil. Here is a reference to the different 
varieties of blood, and Aristotle tells 
us which sort of blood is alo-O^riKuWepov 
and which animals are on that account 
4>povLfxior€ P a (cf 650 b 24 and 686 b 28). 
The phrase aljxaros Kpavis is actually 
used at 686 a 9- (Cf also 650 b 29, the 
Kpacris in the heart ; 652 b 35, the parts 
in the head are colder than the o-vfi- 
fjLerpos KpacrL$ ; 669 a 11, the Kpacris 
of the body ; 673 b 26, its evKpacria.) 

The term o-itt?;£is, which occurs frequently in the 
Uepl Stcu-n/s, is found only once in the De partibus 
at 677 a 14 — bile is said to be a residue or cnVr?/^?. 
Properly speaking, o-i'm/£is is the term applicable to 
the " colliquesccnce " or decay of the parts of the body 
themselves. (Cf avvr^yixa at De gen. an. 724 b 26 
foil.; also <x)W7/£k, 456 b St; cf. also PJatt's note 
at the end of his translation of De gen. an. ,on 724 b 27.) 
The effect of the colliquescence is to produce an 

° The adjective used is <f>p6vifios. 



unhealthy a7roK/tHo-i? (abscession) — a very common 
term in Hepl Siau^? (see chh. 58 foil, throughout). 
It occurs twice in De partibus. In both places it is 
used of a 7T€piTTo>/xa. At 690 a 9 the surplus earthy 
matter diroKpio-Lv Xafifiavzt, and forms a continuous 
nail or hoof. At 681 b 35 Aristotle speaks of the 
place where the o-n-epfxaTLKi) or the Tre/jiT-co/zan/ci?) 
d7r6Kpi<rL<; is effected ; and here d-nOKpto-L? seems to 
mean simply " act of excretion." The meaning of 
the term seems both here and in Hippocrates to be 
specially associated with -n-e /httgj fiaro., either useful 
ones, or useless and even harmful ones. A great 
deal of ITept Snxi'ti/s is taken up with suggestions for 
getting rid of harmful d7roKp[(rei$. 

The meaning of diroKpuTis is therefore wider than 
" excretion " or " secretion," as used in their present 
usual sense, though these are included among its 

Tb fiaWov Kal fjTTov, " the more and less," see 
above, p. 19, and Gen. An. (Loeb), Introd. g§ 70 ff. 

Translations of Aristotle's Zoology 

The history of the translation of Aristotle's works Transia- 
begins with the Nestorian Christians of Asia Minor, A n° tone's 
who were familiar with the Greek language as their zoological 
service-books were written in it, and before the 
coming of the Arabs they had translated some of the 
works of Aristotle and Galen into Syriac. Before 



435, Ibas, who in that year was made Bishop of 
Edessa, had translated into Syriac the commentaries 
of Theodore on the works of Aristotle. Jacob, one 
of Ibas's successors at Edessa (d. 708), translated the 
Categories into Syriac, but a much earlier version had 
been made by Sergios of Resh *Aina (d. 536), who 
had studied Greek at Alexandria. In 765 the Nes- 
torian physician Georgios was summoned to Bagdad 
by the Caliph, and translated numerous Greek words 
into Arabic for him. By the beginning of the ninth 
century, translation was in full swing at Bagdad, 
under the Caliphate of al-Mamun (813-833), son of 
Harun-al-Rashid. The first leader of this school 
of translators was the physician Ibn al-Batriq, who 
translated the Historia animalium^ the De partibus 
animalium, and the De geiieratione animalium into 

But it was through southern Italy, Sicily and Spain 
that the transmission of Aristotle's works from the 
Arabic into Latin was effected. Messina had been 
recovered from the Saracens by 1060, and the whole 
of Sicily was freed by 1091. Under the Norman 
kings, Greeks, Saracens and Latins lived together 
in one community, and the court was the meeting- 
ground for eminent persons of all nations and 
languages. The reconquest of Spain had begun in 
the eighth century, so that here also an opportunity 
offered for making the works of Greek science 
available in Latin. Archbishop Raymond of Toledo 
(1126-1151) and Bishop Michael of Tarazona (1119- 
1151) were the patrons of the translators, who made 
Toledo the centre of their activity. One of these 
was Michael Scot. 

There is in existence an Arabic translation of 



the zoological works, of which there is a ms. in 
the British Museum." It is probable that this is the 
translation made by Ibn al-Batriq, and that this 
Arabic version is the original from which Michael 
Scot made his Latin translation at Toledo. 6 Michael 
was, among his other accomplishments, astrologer to 
Frederick II., King of Sicily, at his court at Palermo, 
and before 1217 he had reached Toledo and was at 
work there on his translations from the Arabic. His 
De animalibus (a translation of the zoological works in 
nineteen books) is one of his earliest works, and two 
mss. of it c contain a note which gives a later limit 
of 1220 for the work. Other evidence d establishes 
that it was certainly finished before 1217, and it may 
even be placed in the first decade of the century. 
It is probable that Michael had as collaborator one 
Andrew, canon of Palencia, formerly a Jew. One 
of the earliest to make use of Michael's transla- 
tions was Robert Grosseteste/ Bishop of Lincoln 
(d. 1253), one of the leading Aristotelian scholars 
of the time, who quotes from Michael's version of 

° B.M.Add. 7511 (13th-Uth century). This is the ms. 
referred to by Steinschneider, Die arabischen Ubersetzungen 
p. 64. as B.M. 437. I have seen this ms. 

b Judging from the passages which Dr. R. Levy kindly 
read for me in the Arabic ms., the Latin version is a close 
translation from it. Also, the contents-preface which is found 
prefixed to Michael Scot's translation corresponds exactly 
with the preface which precedes the Arabic version in this 
ms. (see the B.M. catalogue, Catalogus codicum manuscrip- 
torum orientalium, p. 215). 

c One of them is ms. Caius 109, in the library of Gonville 
and Caius College, Cambridge. It is of the thirteenth 

d See S. D. Wingate, The Medieval Latin Versions^ p. 75. 
9 Born at Stradbroke, Suffolk. A Franciscan. 



De generatione. a The De animalibus also formed the 
basis of a commentary in twenty-six books by 
Albert us Magnus. b This was probably written soon 
after the middle of the thirteenth century. Except 
for the portions which appear in Albertus's com- 
mentary, and the earlier part of the first chapter, 
Michael's version has never been printed in extenso. 
Michael died in or before 1235, and is reputed to 
have been buried, as he was born, in the lowlands of 

About the same time, at the request of a pupil of 
Aibertus, St. Thomas Aquinas (1227-1274), who re- 
quired more accurate versions for his commentaries 
on the works of Aristotle, new translations, direct 
from the Greek, were being undertaken by William 
of Moerbeke. d William was born about 1215. He 
became a Dominican, was confessor to Popes Clement 
IV. and Gregory X., and was Archbishop of Corinth. 
He acted as Greek secretary at the Council of Lyons 
in 1274. He died in 12S6. The earliest dated trans- 
lation made by him is one of the Departibus animalium. 
The date 1260 occurs in a ms. of it at Florence (Fae- 
sulani 168), which also contains Hist. an.,Deprogressu 
an., and De gen. an. This translation was made at 

Among later Latin translators of the zoological 

a According to Roger Bacon, Michael appeared at Oxford 
in 1230, bringing with him the works of Aristotle in natural 
history and mathematics. 

b Ed. princeps, Rome, 1478 ; latest ed., H. Stadler, 

« 639 a 1—640 a 20, printed by G. Furlani in Rivista 
degli Studi Orientals ix. (1922), pp. 246-249. 

d A small town south of Ghent on the borders of Flanders 
and Brabant. 


works the names of two Greeks must be mentioned. 
George of Trebizond (Trapezuntius), who was born 
in Crete in 1895, visited Italy between 1430 and 
1438, and was secretary to the humanist Pope 
Nicholas V., an ardent Aristotelian. George's work, 
however, was hurried and not over-exact, and he, 
together with his predecessors, was superseded by 
his contemporary Theodore of Gaza, who was born 
in Thessaloniea about 1400, and was professor of 
Greek at Ferrara in 1447. In 1450 Theodore w r as 
invited by the Pope to go to Rome to make Latin 
versions of Aristotle and other Greek authors. His 
translation of the zoological works,* 1 dedicated to the 
Pope, Sixtus IV., soon became the standard version, 
and it is printed in the Berlin edition of Aristotle. 

Translations of the De ge?i. were made by Augus- 
tinus Niphus, of the University of Padua (1 1<73-1546), 
and of the De gen. and De incessu by Peter Alcyonius 
(Venice, 1487-1527). The Dege?i. was also translated 
by Andronieus Callixtus of Byzantium (d. 1478). 
With the later Latin versions we need not here 
concern ourselves, but something must be said of 
the scientific workers who were inspired by Aristotle, 
and of the translations into modern languages. 

The Renaissance biologists show unmistakably the Aristotle's 
difference in quality which there is between Aristotle's successors, 
physics and his biology. Hieronimo Fabrizio of 
Aequapendente (1587-1619) knew and admired 
Aristotle's work on embryology, and what is more, 
himself carried out further important observations 
on the same subject. His brilliant successor, William 
Harvey (1578-1657), was a student of Aristotle, and 

a In eighteen books, excluding the spurious tenth book of 
the Historla animalium, 



much of his inspiration came from that source. 
William Harvey was the first to make any substantial 
advance in embryology since Aristotle himself. But 
this is more appropriate to the De generatione than 
to the De pariibus. In other departments of study, 
however, during the seventeenth century, the 
authority of Aristotle and the scholastic doctrine 
with which he was identified were being combated 
in the name of freedom, and thus it came about that 
the zoological works also, which had been brought 
to light by the dark ages, were allowed to pass back 
into oblivion by the age of enlightenment. They were 
not rediscovered until the end of the eighteenth 
century by Cuvier (1769-1832) and Saint-Hilaire 
(1805-1895) in the nineteenth. 

Modern Editions 

1. The Berlin edition of Aristotle, bv Immanuel Bekker. 

Vol. i. (pp. G30-G97) includes P.A. Berlin, 1831. 
1a. The Oxford edition (a reprint of the preceding). Vol. v. 
includes P.A. Oxford, 1837. 

2. One-volume edition of Aristotle's works, by C. II. Weise 

(pre-Bekker text). Leipzig, 1843. 

3. The Leipzig edition. Vol. v. contains P.A,, edited and 

translated into German by A. von Frantzius. Leip- 
zig, 1853. 

4. The Didot edition. Vol. iii. includes P.A, Edited by 

Bussemaker. Paris, 1854. 

5. The Teubner edition. Edited by Bernhardt Langkavel. 

Leipzig, 1868. 

G. The Bude edition. Edited by Pierre Louis. With a 
French translation and notes. Paris, 195G. 

Translations without Text 

7. Thomas Taylor. English translation of Aristotle in ten 


volumes. Vol. vi. includes P.A. (pp. 3-163). London, 

8. F. N. Titze. German translation of Book I. In his 

Aristoteles ilber die wissenschaftliclte Behandlungsart 
der Naturkunde. Prague, 1819. 

9. Anton Karsch. German translation. Stuttgart, 1855 

(second ed., Berlin, 1911). 

10. William Ogle. English translation, with notes. Lon- 

don, 1882. 

11. J. Barthelemy-Saint-Hilaire. French translation, with 

notes. Paris, 1885. 

11. William Ogle. English translation, with notes (a re- 

vision of No. 10). Oxford 1911. 

12. Francisco Gallach Pales. Aristoteles : Obras com- 

pletas. Vol. X contains Be partibus and De incessu 
animalium. Spanish translation, without notes. Vol. 
lxii. of Nueva Biblioteca Filosofica. Madrid, 1932. 

Langkavel reproduces almost verbatim the Berlin 
text, together with Bekker's apparatus, to which a 
great deal of other matter has been added, including 
some of Bekker's ms. notes in his copy of Erasmus's 
edition, and some corrected reports of the readings 
of the ms. E, which Langkavel himself inspected. 
Also, there are some emendations proposed by 

Any English translator must stand very much 
indebted to the work of William Ogle, whose trans- 
lation, originally published in 1882, was revised by 
its author and republished in the Oxford series of 
translations of Aristotle in 1911. It is not possible 
to overrate the care and exactness with which this 
piece of work was executed. I should like here to 
acknowledge my own indebtedness to it, and I have 
had its accuracy as a model before me. With re- 
gard to style, it will be seen that I have aimed at pro- 
ducing something rather different from Ogle's version. 



The Text 

The mss. The manuscript authorities cited by Bekker for the 
De partibus will be found on p. 50. 

The dates of some of the mss. as given by different 
scholars vary considerably : for details I refer the 
reader to the various catalogues, and also to L. Ditt- 
meyer's edition of Hist. an. (Leipzig, 1907) and W. W. 
Jaeger's edition of De an. motu, etc. (Leipzig, 1913). 
Restoration I have relied upon the apparatus of Bekker and 
of the text. L an gk ave ] for the readings of the Greek mss., except 
for those of Z, the oldest parts of which I have collated 
from photostats a ; and at several places I have in- 
spected the ms. itself. In some places (e.g. 663 b 17, 
685 a 2, 16) I found the reading had been defectively 
reported. It is clear that a more reliable collation of 
the chief mss. of De partibus is clearly needed. From 
a different source I have attempted to restore intelligi- 
bility to several corrupt passages with the aid of the 
Arabic version and the Latin version of Michael 
Scot, which represent an earlier stage of the Aristo- 
telian text than our Greek mss. Among the passages 
dealt with in this way are the passage at 654 b 14 
following, which has been dislocated by glosses and 
phrases imported from elsewhere, and the remark- 
able passage about the structure of the Cephalopods 
at 684 b 22 following, where considerable havoc has 
been done to the text by references to a diagram 
which were inserted at some period between the 
date of the ms. from which the Arabic version was 
made and that of the archetype of all our present 
Greek mss. I have been able to restore this passage, 
though not always the actual Greek words, by refer- 
ence to the Arabic version and Michael Scot's Latin 
a See additional note on p. 434. 



translation made from it. Dr. Reuben Levy has 
most kindly read this passage for me in the 13th-14th 
century Arabic ms. in the British Museum, Add. 7511. 

For these two passages, and for a good many other 
suspected places, I have consulted all the known mss. 
of Michael Scot's version which are to be found in 
this country. They are (excluding mss. which contain 
merely abridgements or extracts) : 

Cambridge, Gonville and Caius College 109 
University Library Ii. 3. 16 
„ * „ Dd. 4. 30 
Oxford, Merton College 278 
„ Balliol College 252 
London, British Museum Roval 12. C. XV 
„ Ha'rl. 4070 ° 

All these are of the thirteenth or fourteenth 

I have inspected at test places the following three 
mss. of William of Moerbeke's version : 

Oxford, Merton College 270 
» 271 
„ Balliol College 250 

William's translation was made from a ms. or mss. 
which had already been infected by the corruptions 
found in the Greek mss. which exist to-day. 

I should like here to express my thanks to the 
Librarians who so kindly made arrangements for me 
to inspect the mss. under their care. 

Where I have accepted the reading of the Berlin Scopp of 
edition, I have not given any record of the ms. vari- criticul? 
ants. These are to be found in the apparatus criticus 
of that edition and of Langkavel's edition. 

° So far as I know, this ms. has not been mentioned in any 
of the published lists of mss. of Michael Scot's De animalibus. 



I have endeavoured, except in the passage 
691 b 28 to 695 a 22 in the fourth Book, to record 
all places where I have departed from the text of 
the Berlin edition, and I have given the source of 
the reading which I have adopted. Where Bekker 
himself introduced a reading different from that of 
the mss., this is attributed to him by name. 
Punchia. I have not recorded all of the many passages in 
tl0n * which I have corrected the punctuation. The text 
has been reparagraphed throughout. 


Short bibiio- The following list includes authorities for state- 
graph}. njen ^ g ma( j e j n Introduction, and books which 
the student of the Aristotelian zoological works and 
their history will find useful : 

C. H. Raskins, Sttidics in the History of Medieval Science, 

ed. 2, Cambridge, Mass., 1927. 
W. Jaeger, Aristotle (English tr. bv R. Robinson), Oxford, 


L. Leclerc, Ilistoire de la medecine arabe, Paris, 1876. 

T. E. Loncs, Aristotle's Researches in Xatural Science, 

London, 1912. 
W. D. Ross, Aristotle, London, 1930. 

J. E. Sandvs, A History of Classical Scholarship, Cam- 
bridge," 1908-1921. 

C. Singer, Studies in the History and Method of Science, 
Oxford, 1921. 

C. Singer, Greek Biology and Greek Medicine, Oxford, 1922. 
M. Steinschneider, Die arabischen Ubersetzungen aus dem 

Griechischen (Beiheft XII. zrnn Centralblatt fiir 

Bibliotbekswesen), Leipzig, 1893. 
M. Steinschneider, Die europdischen Ubcrsetzungen aus dem 

Arabischen, in Sitzungsberichte d. kais.Akad. der Wiss., 

cxlix., Vienna, 1905. 
D'Arcy W. Thompson, Growth and Form, Cambridge, 

1917 (new ed., 1942). 



D'Arcy W. Thompson, Essay on " Natural Science " in 
The Legacy of Greece, Oxford, 1924. 

S. D. Wingate, The Medieval Latin Versions of the Aristo- 
telian Scientific Corpus, London, 1931. 

F. Wustenfeld, Die Ubersetzungen arabischer Werke in das 
Lateinische, in Abhandlungen der k. Gesell. d. ]Viss. 
zu Gottingen, xxii., 1877. 


It is a great pleasure to acknowledge here the help 
which I have received from many friends at Cambridge, 
not only by way of reading typescript and proof and 
by discussion, but also by the interest which they 
have shown in the work and by their continuous 
encouragement. The following have read the trans- 
lation either in whole or in part : Prof. F. M. Corn- 
ford, Professor of Ancient Philosophy ; Dr. F. H. A. 
Marshall, Reader in Agricultural Physiology (who has 
also kindly written the Foreword to this volume), 
and Dr. Joseph Needham, Reader in Biochemistry. 
I am under a particular obligation to my colleague 
Mr. H. Rackham, who has read the whole translation 
both in typescript and in proof. I am indebted 
to Dr. Sydney Smith and a number of other friends 
for their kindness in discussing various points and 
for reading certain passages. Dr. Reuben Levy, 
Professor of Persian, has kindly read for me some 
passages in the Arabic translation of the zoological 
works. To all of these gentlemen, without whose 
aid the work could not have been carried through, 
I record my sincerest thanks. 

The present (third) edition has again been revised. 

A. L. P. 

July 11th 1952 



E Parisinus regius 1853 (see p. 434) 
Y Vaticanus graecus 261 

Z Oxoniensis Coll. Corp. Chr. W.A. 2. 7 (see p. 434, 

U Vaticanus 260 

P Vaticanus graecus 1339 

S Laurentianus Mediceus 81. 1 

Q Marcianus 200 

b Parisinus 1859 

77i Parisinus 1921 

2 Michael Scot's Latin version, from my 

own transcription. 

The usual reading, as in the Berlin 

Emendations proposed by Langkavel in 
his edition. 

Emendations proposed by William Ogle 
in footnotes to his translation. 
Emendations proposed by Arthur Piatt, 
either (a) in " Notes on Aristotle," in 
Journal of Philology, 1913, xxxii. 292 
following, or (/>) recorded by Ogle in 
footnotes to his translation. 
Suggestions in private communications 
to me from Professor Cornford and Mr. 

Ch. Thurot, in Rev. Arch., lS67. a 
Emendations proposed by myself. 





Cornford \ 


a Of over 100 textual points, many being of minor import- 
ance, raised by Th., about a third had been dealt with in my 
first edition (before Th.'s work came to my notice), some of 
them more fully, by other scholars or myself. Some of Th.'s 
other suggestions have been adopted in this edition. 

The maister Cooke was called Concoction. 

Spenser, Faerie Queen 



639 a Tie pi rraoav dcujpiav re Kal peQohov, opotcog 
rancivoripav re Kal TipicoTepav, hvo Saivovrai 
TpOTTOi rrjs e^ecos eivcLLj tov ry-jv pev €77 LGTy'jprjV 
rod Tpdyparos KaXtos e^et TTpoaayopevetv, rrjv S' 
5 otov TraiSeiav Tivd. rre-aioevpevov yap iuri Kara 

TpOTiOV TO hvi'auOai KpiVdl €VG~6yLQ$ TL KaXd)£ Tj pTj 

KdXcos olttoSlBcoglv 6 Xeycov . roLovrov yap orf nva 
Kal rov oXcos 77 erraioevpevov olopeB* elvai, Kal to 
7T€77ai$€VGQai to ovvauOai TTOielv to eiprjpevov. 

TrXrjV TOVTOV p€V 77 € pi Trdl'TOJV WS €L77€LV KpLTLKOV 

io Tiva vopltopev elvat era tov dpiOpov 6vtq. } tov ok 
nepl tlvos cJ)VG€Cl)s dj)OJpiGpivrjS' e'lrj yap dv ti$ 
eTepog tov avTov TpoTTOv TO) elprjpeva) hiaKeipevos 

77€pl pdplOV. 0)GT€ ofjXoV OTl Kal TTjS ~€pl <f)VGLV 

LGTOptas Set TLvds vrrdpyjav opovs tolovtovs 77pds 
ov$ dva(/>€pu)v drroSe^eTat tov Tporrov tojv heiKw- 



There are, as it seems, two ways in which a 
person may be competent in respect of any study or 
investigation, whether it be a noble one or a humble : 
he may have either what can rightly be called a 
scientific knowledge of the subject; or he may have 
what is roughly described as an educated person's 
competence, and therefore be able to judge correctly 
which parts of an exposition are satisfactory and 
which are not. That, in fact, is the sort of person 
we take the " man of general education " to be ; his 
" education " consists in the ability to do this. In 
this case, however, we expect to find in the one 
individual the ability to judge of almost all subjects, 
whereas in the other case the ability is confined to 
some special science ; for of course it is possible to 
possess this ability for a limited field only. Hence 
it is clear that in the investigation of Nature, or 
Natural science, as in every other, there must first 
of all be certain defined rules by which the ac- 
ceptability of the method of exposition may be 
tested, apart from whether the statements made 



15 fievajv, x co P i ^ TOV 776051 e X et TCLArjues, eire ovrcos 
eure aAAcus". Aeya; 8' otoy irorepov Set Xafifidvovras 
\iiav eKaarrjv ovaiav Trepl Tavrrjs oiopl^etv KaQ' 
avrrjVy otov Trepl avQpumov cj>voecDS fj Xeovros 77 

fioOS Tj KCLL TWOS dXXoV eKGLGTOV 77pO^€tpi^O- 

fievovs, 7) ra Kotvfj ovfifiefirjKora tt&gl Kara tl 
kolvov vTroOefievovs — 7roAAa yap vnapx^L ravra 

20 7ToXAols yeveoiv ere pots ovaiv dAA^Aa;!^ otov vttvos, 
avcLTTvorj, av^-qoLs, (f)9cuL9 } ddvaros, Kal rrpos tov- 
tols oaa roiavra row XeLuofxevajv uaQuiv re Kai 
hiaOeaewv aSyXov ydp Kal dhiopiorov ian Xeyeiv 
vvv Trepl tovtcov (f>avepov 8' otl Kal Kara fiepos 
fiev Xeyovres Trepl ttoXXwv epovfiev TroXXaKts ravrd' 

25 Kal yap lttttols Kal kvctI Kal avOpamots VTrdp)(ei 
rcov slprjfievcov eKaorov, ajcrre eav Ka9* eKaarov rd 
crvfJLPefirjKOTa 1 Xeyrj tls, rroXXaKLS dvayKauO^aerai 
rrepl to)v avrcov Xeyeiv, b'oa ravrd fiev vrrdp)(ei rots 
eiSei 8ta(f)epovGL rcov ^tptov, avra oe firjoepiiav eyei 

30 oia(j>opdv. erepa 8' luoj? eurlv ots ovfifialveL rr)v 
639 b {lev Karrjyoplav eyew avrrjv Bta^epetv 8e rfj 

Kar ethos oia<f>opa> otov rj rcov ^tpcvv Trope la- ov 
yap (f>aLverai fita rco eiSer otacfrepei yap rrrrjuLs Kal 
vevuts Kal fidoLcns Kal epiftis. 

Ato Set p.r) otaXeXrjOevai ttcos err io Kerr r eov s Xeyco 
6 Se irorepov Kotvfj Kara yevos Trptorov, eW^ varepov 

1 ra ovufiefirjKQTa Ogle : rcov ovufiefirjKQTQjv vulg. 



represent the truth or do not. I mean, for instance, 
should we take each single species severally by turn 
(such as Man, or Lion, or Ox, or whatever it may 
be), and define what we have to say about it, in and 
by itself ; or should we first establish as our basis the 
attributes that are common to all of them because 
of some common character which they possess ? — there 
being many attributes which are identical though 
they occur in many groups which differ among them- 
selves, e.g. sleep, respiration, growth, decay, death, 
together with those other remaining affections and 
conditions which are of a similar kind. I raise this, 
for at present diseussion of these matters is an obseure 
business, laeking any definite scheme. However, 
thus much is plain, that even if we discuss them 
species by species, we shall be giving the same de- 
scriptions many times over for many different animals, 
since every one of the attributes I mentioned occurs 
in horses and dogs and human beings alike. Thus, 
if our description proceeds by taking the attributes 
for every species, we shall be obliged to describe the 
same ones many times over, namely, those which 
although they occur in different species of animals are 
themselves identical and present no difference what- 
ever. Very likely, too, there are other attributes, 
which, though they come under the same general 
head, exhibit specific differences ; — for example, the 
locomotion of animals : of which there are plainly 
more species than one — e.g. flight, swimming, walk- 
ing, creeping. 

Therefore we must make up our minds about 
the method of our investigation and decide whether 
we will consider first what the whole group has in 



rrepl tcov ISlojv Oeajprjreov, r] Ka6' eKaoTOV evOvs. 
vvv ydp ov StajpLuraL rrepl avrov, ovSe ye to vvv 
prjOrjoofievov, otov rroTepov KaOdrrep ol fiaQ-qnarLKol 
ra 7T€pl ttjv aarpoXoylav SeiKvvovaiv, ovtw Set Kal 


10 Oecoprjoavra Kal ra fiepr) ra TTepl eKaarov, eireid^ 
ovtw XeyeLv to olol tl Kal tols atrta?, rj dXXws ttws. 
rrpos oe tovtols, euel TrXeiovs opcbfiev alrLas rrepl 
rrjv yeveoKV ttjv (fivoiKiqv, otov ttjv ov eveKa Kal 
ttjv b'Qev r) apxrj rrjs KLvrjuecns, oiopioreov Kal 
nepl tovtwVj rrola TTpcoTrj Kal Sevrepa Tre<f)VKev. 

is <f>aiveTai Se TTpajTY} rjv Xeyofiev eveKa tlvos' Xoyos 
yap ovtos, &PXV ° Xoyos SfiOLUJs ev re Tots 
Kara Teyyr\v Kal ev tols (f>voei aweoTr\Ko<jLv . rj 
yap Tjj Scavola. r) rfj alaOrjaei opLadfievos 6 puev 
laTpos TTjv vyieiav 6 8' OLKoSofios ttjv otKtav, 
ciTToStSoaat tows' Xoyovs Kal tols aiTias ov ttolouglv 
€.k6lotov } Kal Slotl TTOtrjTeov ovtojs* fiaXAov 8* 

20 earl to ov eveKa Kal to KaXov ev tols ttjs (frvo-ecos 
epyois rj ev tols tt)s Texvrjs* to 8' i£ dvdyKrjs 
ov 7raaiv v7rapxeL tols /cara ())volv 6{jlolojs, els 

a This point is resumed and decided below, 644 a 23 ff., 
645 b 2 ff. 

6 " Causes." See Introduction, pp. 24 ff. 

e " Formation." See Introduction, pp. 27 f, 

d i.e. the " final " cause. 

e i.e. the " motive " or " efficient " cause. 

' See Introduction, pp. 26 f. * Cf. 645 a 24. 



common, and afterwards the specific peculiarities ; 
or begin straightway with the particular species. 
Hitherto this has not been definitely settled. And 
there is a further point which has not yet been 
decided : should the student of Nature follow the 
same sort of procedure as the mathematician follows 
in his astronomical expositions — that is to say, 
should he consider first of all the phenomena which 
occur in animals, and the parts of each of them, and 
having done that go on to state the reasons and the 
causes ; or should he follow some other procedure ? 
Furthermore, we see that there are more causes b 
than one concerned in the formation c of natural 
things : there is the Cause for the sake of which the 
thing is formed/ and the Cause to which the begin- 
ning of the motion is due. 6 Therefore another point 
for us to decide is which of these two Causes stands 
first and which comes second. Clearly the first is 
that which we call the " Final " Cause — that for the 
sake of which the thing is formed— since that is 
the logos f of the thing — its rational ground, and 
the logos is always the beginning for products of 
Nature as well as for those of Art. The physician 
or the builder sets before himself something quite 
definite- — the one, health, apprehensible by the 
mind, the other, a house, apprehensible by the 
senses ; and once he has got this, each of them 
can tell you the causes and the rational grounds 
for everything he does, and why it must be done 
as he does it. Yet the Final Cause (purpose) and the 
Good (Beautiful) 9 is more fully present in the works 
of Nature than in the works of Art. And moreover 
the factor of Necessity is not present in all the 
works of Nature in a similar sense. Almost all 



639b « ~ / *l * W 

o Tteipojvrai iravreg ax^oov rous Aoyovs avayew, 
ov SieXofxevoL TToaax&S Xeyerai to avayKalov. 
vrrapx^i 8e to /xev drrXtbs rots ollSlolSj to 8' i£ 

25 V7To04u€O)S KGU TOt? €V y€V€<7€L TTOicJLV WGTTCp €V 

rots Te^vaarot?, otov ot/cta /cat twv aXXojv otcoovv 
rtov ToiovTtov. dvdyKTj 8e rotdvSe rr}v vXrjv vtt- 
dpgai el earai ot/cta rj dXXo n reXos' kol yeveaOat 
re /cat KivrjOrjvaL 8et rdSe TTpwrov, elra ro8e, /cat 

TOVTOV Srj TOV TpOTTOV €<j>€^rjs ^XP 1 T & 0V S KaL 

30 ov eveKa ytWrat eKaarov /cat ecrrtv. wcravrcog Se 
640 a /cat eV Tot? cf>vo*€L yivopiivois . aAA' o rporros rrjs 
aTToSel^eaJS /cat ttJs" dvdyKrjs erepos eirl re rrjs 
<j)VULKrjs /cat tcoi/ OetoprjrLKwv irrtGrrjfxcov, (elprjrat 
8' eV irepois Trepl tovtcqv.) rj yap dpXTj to is fiev to 
ov, rots Se to iaopLevov iirel yap tocovS* ecrrtv rj 
6 vyUia rj 6 dv9pa)7TOSy dvdyKTj to8' etvai rj yevioQai, 
aAA' ou/c eirel roS' ecrrtr 7) yeyo^ev, e/cetvo 

a '* Absolute," i.e. simple or unconditional necessity, 
belongs to the " eternal things," such as the heavenly bodies 
or the eternal truths of mathematics. For further details 
see De gen. et corr. 337 b 14 ff. 

b At Met. 1025 b ft*. Aristotle makes a threefold classifica- 
tion of the sciences into (a) theoretical (contemplative), 
(6) practical, (c) productive. The result of (a) is knowledge 
only, of (6) knowledge and action, of (c) knowledge, action, 
and some article or product. The three " theoretical " 
sciences are theology (i.e. metaphysics), mathematics, and 
physics (natural science). In the present passage, however, 
Aristotle contrasts natural science with the " theoretical " 
sciences. This is because he is considering Nature as a 
craftsman whose craft or science belongs to the third class — 
the ** productive " sciences. Our study of Nature's science 



philosophers endeavour to carry back their explana- 
tions to Necessity ; but they omit to distinguish the 
various meanings of Necessity. There is " absolute " 
Necessity, which belongs to the eternal things ; and 
there is " conditional " Necessity, which has to do 
with everything that is formed by the processes of 
Nature, as well as with the products of Art, such as 
houses and so forth. If a house, or any other End, 
is to be realized, it is necessary that such and such 
material shall be available ; one thing must first be 
formed, and set in motion, and then another thing ; 
and so on continually in the same manner up to the 
End, which is the Final Cause, for the sake of which 
every one of those things is formed and for which it 
exists. The things which are formed in Nature are 
in like case. Howbeit, the method of reasoning 
in Natural science and also the mode of Necessity 
itself is not the same as in the Theoretical sciences. 
(I have spoken of this matter in another treatise. 5 ) 
They differ in the following way. c In the Theoretical 
sciences, we begin with what already is ; but in 
Natural scienee with what is going to be : thus, we say, 
Because that which is going to be — health, perhaps, or 
man— has a certain character, therefore of necessity 
some particular thing, P, must be, or must be formed ; 
not, Because P is now, or has been formed, therefore 
the other thing (health, or man) of necessity is now 
may be a " theoretical " science, but Nature's science itself 
is " productive." 

c The reasoning process in a " theoretical " science, e.g. 
mathematics, begins, say, with A, and then deduces from it 
the consequences B, C, D. In a " productive " science, 
e.g. building, it begins with the house which is to be built, 
D, and works backwards through the preliminary stages 
which must be realized in order to produce the house, 
C, B, A. Of below, 640 a 16 ff. 

c 59 


avdyicqs iorlv fj earat. Oi)8' eanv els alhiov ovv- 
aprrjoaL rrjs TOiavrr]s diroSeL^ecos rijv avayKTjV, 
war elireTv, iirel to8* Iot'lv, otl rdS' Zotlv. St- 


10 Aet Se fir} XeArjOevdL kcll irorepov irpoarjKeL XeyeLV, 
a>G7T€p ol TTporepov irroLovvro tt)v OecopLaVj 7TU)5 
eKaoTOV yiveoOaL 7rd<f)VK€ [i&XXov rj ttws €otlv, 


§* ivrevOev dpKriop ekt (KaOdrrep koll irporepov 

el7T0[JL€V y OTL 7TpO)TOV T(Z <f)aLv6{JL€Va Xrj7TT€OV TTCpL 

15 €Kaurov yevos t effi ovrco ra? curia? tovtcov 
XeKreov) kcll 7repi yeveaecos' (idXXov ydp rd$€ 
ovufiaLveL kcll irepl rrjv OLKoSofirjoLV iirel toio'vS' 
earl to etoog rrjs olkicls, rj tolovo* Igtlv r) olklcl otl 
yiveraL ovtcos. r) yap ylveGLS eveKa ttJ? ovoLas 
egtlv, dAA' oi>x rj ovola eveKa rrjs yevcaetos* OLoirep 

20 *Epl7T€00kXt)s ovk opBcbs €Lp7]K€ Xeycov vrrdpxew 
77oAAa rot? l^wols Sid to ovfifirjvaL ovrcos ev rfj 
yev€0€L t olov Kal rrjv pcr^iv TOLavTrjv £X €LV ° TL 
orpacf>dvTos KaraxOrjvaL ovvifir], dyvowv irpujTov fiev 
otl Set to OTrepfia to ovvLOTav 1 virdpxzw TOLavrrjv 

1 avvioTav Piatt : ovotclv vulg. 

° Though of course this Necessity has its place in natural 
science (see 649 a 31 ff.). It is, however, not the only sort 
of Necessity in Natural science, and not the paramount one. 

6 See De gen. et corr. 337 b 25 ff. An example of a non- 
convertible proposition is : Foundations are necessary for a 
house to be built. You cannot say, " If foundations are laid 
a house must of necessity be built," because it is not ** ab- 
solutely " and always necessary that a house should be built 

c Of. Plato, Philebus 54 a-c. 



or will be in the future. a Nor, in a process of 
reasoning of this kind, is it possible to trace 
back the links of Necessity to eternity, so as to say, 
Because A is, therefore Z is. I have, however, dis- 
cussed these matters in another work, 6 and I there 
stated where either kind of Necessity applies, which 
propositions involving Necessity are convertible, and 
the reasons why. 

We must also decide whether we are to discuss 
the processes by which each animal comes to be 
formed — which is what the earlier philosophers 
studied — or rather the animal as it actually is. 
Obviously there is a considerable difference between 
the two methods. I said earlier that we ought first 
to take the phenomena that are observed in each 
group, and then go on to state their causes. This 
applies just as much to the subject of the process of 
formation : here too we ought surely to begin with 
things as they are actually observed to be when 
completed. Even in building the fact is that the 
particular stages of the process come about because 
the Form of the house is such and such, rather than 
that the house is such and such because the process 
of its formation follows a particular course : the 
process is for the sake of the actual thing, the thing 
is not for the sake of the process. So Kmpedocles 
was wrong when he said that many of the character- 
istics which animals have are due to some accident 
in the process of their formation, as when he 
accounts for the vertebrae of the backbone by say- 
ing d " the fetus gets twisted and so the backbone 
is broken into pieces " : he was unaware (a) that 
the seed which gives rise to the animal must to 
d Emped. frag. 97 (Diels, Fragment e* t 31 b 97). 



exov hvvafiiv, eW' otl to iroirjaav TTporepov vrrrjpx^ 
25 ov \iovov ra> Xoycp dAAa Kai tlu xpovoj- yevva yap o 
dvOpcoTTOs avOpcoTTOVy ware Sta to eKelvov toioVS' 
etvai r) yeveoLS roidhe avpL^alveL tojSi. [SfxoLOJS 
he kclI enl tojv avroybdrajs Bokovvtojv yiveuOai 
KaOdirep Kai errl tojv Texvo:oTdjv k'vta yap 1 Kai ajro 
ravrofjudrov yiverai ravrd tois" arret Tex}^S } oiov 
so vyUia, ojv" fiev ovv Trpovirapx^ to ttoltjtlkov 
[ofioiov], 2 otov r) A dvhpiavro7TOL7]TiKri , ov [ydp] 5 yi- 
verai avrofiarov. r) he reyyr) Aoyo? rod epyov o 
avev rrjg vX-qs eoriv. Kai rots drro tvx^S ofioLOJS' 
cos" yap r) rexvr} ex^> ovtoj yiverai.Y Sio jLtaAtara 
fiev XeKreov d>s eTreihr) tout' rjv to dvOpcoTTcp eivai, 
35 hid tovto ravr e^er ov yap ivhex^rai elvai avev 
tojv jJLopiwv tovtojv. el Be [XT}, 6 tl eyyvTara 
TOVTOV y Kai rj otl oXojs dhvvaTOV dXXcos, 1 r) KaXoas 
640 b ye cvtojs. rauTa 8' eVerac etrel 8' eoTi tolovtov, 
ttjv yeveoiv whl Kai TOiavTrjv avfifiaiveiv dvay- 
KaZov Sio yiveTat TTpwTov tojv fioplojv Tohe, eiTa 
ToSe. Kai tovtov Brj tov Tporrov opboicos errl ndv- 
tojv tojv <j)voei owLOTafJLevojv . 
5 Ot fiev ovv dpxaioi Kai rrpajTOL <f>iXoao<f>r}cravT€$ 

1 evia yap om. Z 1 . 

2 c5v Z : rcov vulg. 

3 om. Z 1 . 

4 t) Z : om. vulg. 

5 om. Z. 

6 ofioiws (1. 27) . . . yiWcu, ex Met. 1032-1034 exorta. 
olim ut vid. in marg. 610 b 4 acUcripta ; inepta seclusi. 

7 otl oXqjs Z 1 : oXqjs otl a. a. vulg. 

° i.e. the same character as the animal which it is to pro- 
duce. For dynamis see Introduction, pp. 30 ff. 
b No doubt a marginal note appended to 640 b 4. 



begin -with have the appropriate specific character a ; 
and (6) that the producing agent -was pre-existent : 
it was chronologically earlier as well as logically 
earlier : in other words, men are begotten by men, 
and therefore the process of the child's formation is 
what it is because its parent was a man. [Similarly 
too with those that appear to be formed spontane- 
ously, just as with those produced by the arts ; for 
some that are formed spontaneously are identical 
with those produced by art, e.g. health. As for those 
things whose producing agent is prc-existent, e.g. the 
art of statuary, no spontaneous formation occurs. Art 
is the logos of the article without the matter. And 
similarly with the products of chance : they are 
formed by the same process that art would employ.] 6 
So the best way of putting the matter would be to 
say that because the essence of man is what it is, 
therefore a man has such and such parts, since there 
cannot be a man without them. If we may not say 
this, then the nearest to it must do, viz. that there 
cannot be a man at all otherwise than with them, or, 
that it is well that a man should have them. And 
upon this these considerations follow : Because man is 
such and such, therefore the process of his formation 
must of necessity be such and such and take place 
in such a manner ; which is why first this part is 
formed, then that. And thus similarly with all the 
things that are constructed by Nature. 

Now those who were the first to study Nature in 



7T€pl <f>vaews irepl Trjs vXiKTjs dp^rjs Ka ^ TOt " 
auras' curia? Igkottovv s tls Kal 7701a tls, Kal 7tw$ 
€K Tavrrjs yiverai to oXov, Kal tlvos klvovvtos, olov 
veiKovg rj cf)i\La$ r) vov rj tov avTOfiaTOVj Trjs §' 
V7TOK€Lfi€vr)s vXrjs tololvo€ tlvol cf>VGiv i^ovarjs 

10 dvdyKrjs, olov tov piev vrvpos OeppLijv, Trjs oe yrjs 
ifjvxpav, Kal tov [lev Kovcfyrjv, Trjs Se fiapelav. ovtws 
yap Kal tov KoapLov yevvwGLv. opcolws oe Kal irepl 
Trjv twv t^wwv Kal twv <f>vTwv ylveoLV XeyovoLv> 
otov 1 iv TW acofjcaTi peovTOs p.ev tov vbaTOS KotXiav 
yeviaOai Kal irauav vTToSo^rjv Trjs T€ Tpo<f>rjs Kal tov 

15 irepiTTwpLaTos, tov Se 7TvevpLaTos SLarropevOevTos 
tovs fiVKTrjpas dvappayrjvat. 6 S' drjp Kal to vhwp 
vXrj twv owpLaTWv cgtlv £k twv tolovtwv ydp 
owpcaTwv evvLOT&cri Trjv (f>vcrtv rrdvTes. el 8' eoTiv 
6 dvOpwTTOs Kal to. £a>a (f>voei Kal tcl /xopia ai)Twv s 
AeKTtov av 7T€pl crapKos etrj Kal ogtov Kal alfxaTOS 

20 Kal twv opLOLopiepcbv ajravTOov, opLolws Se Kal twv 
dvopioiopiepwv, otov Trpoowrrov, ^ei^d?, ttoSos, fj 
T€ tolovtov eKauTov Iotiv avTwv Kal KaTa TTolav 
Svvajj.LV. ov ydp LKavov to €k tlvwv €utlv } olov 
TTVpos rj y?}S, warrep Kav el irepl kXlvtjs iXeyop.ev rj 
tlvos dXXov twv tolovtwv, irreLpwpLeOa pLaXXov av 

25 SLopl^eLV to ethos avTrjs rj Trjv vXrjVj otov tov ^aA/coy 

1 on post otov vulg. : del. Ogle. 

a As Empedocles and Anaxagoras, whose attempts to 
discover the "material" and the "efficient" causes are 
mentioned a few lines below. See also Met. 9S3 b 6 if . 

b " Material " cause : see Introduction, pp. £?4 ff. 

e " Residue " : lit. " surplus " ; see Introduction, pp. 32 ff. 

d Cf. Hippocrates, TLepl Starry?, i. 9. 

* " Parts " : see Introduction, pp. 2S ff. 



the early days a spent their time in trying to discover 
what the material principle or the material Cause b 
was, and what it was like ; they tried to find out 
how the Universe is formed out of it ; what set 
the process going (Strife, it might be, or Friendship, 
Mind, or Spontaneity) ; assuming throughout that 
the underlying material had, by necessity, some 
definite nature : e.g. that the nature of Fire was hot, 
and light ; of Earth, cold, and heavy. At any rate, 
that is how they actually explain the formation of 
the world-order. In a like manner they describe the 
formation of animals and plants, saying (e.g.) that the 
stomach and every kind of receptacle for food and for 
residue c is formed by the water flowing in the body, 
and the nostril openings are forcibly made by the 
passage of the breath. d Air and water,, of course, 
according to them, are the material of which the body 
is made : they all say that Nature is composed of 
substances of this sort. Yet if man and the animals 
and their parts 6 are products of Nature, then account 
must be taken of flesh, bone, blood, in fact of all the 
" uniform parts," / and indeed of the " non-uniform 
parts " too, viz. face, hand, foot ; and it must be 
explained how it comes to pass that each of these is 
characterized as it is, and by what force this is effected. 
It is not enough to state simply the substances out of 
which they are made, as " Out of fire," or " Out of 
earth." If we were describing a bed or any other 
like article, we should endeavour to describe the form 
of it rather than the matter (bronze, or wood) — or, at 

' " Uniform " and " non-uniform " : see Introduction, pp. 
28 ff. The distinction between " uniform " and ' k non-uniform " 
parts is, historically, the predecessor of the distinction be- 
tween " tissues " and " organs." 



r) to f;vXov, el he. fJLrj, rr\v ye rod ovvoXow kXIvt] yap 
robe ev ra)he rj roBe roLov8e y ware Kav irepl rod 
^XVI J ' aros € 'fy XeKreov, Kal ttolov ttjv ISeav r) yap 
Kara rrjv [xop<j>rjV <f>vois KVpiojrepa rrjs vXiKrjs 

30 Et {Jiev ovv rep oyr\\xari Kal rto y^poy\iari eKaorov 
€ot i rtov re ^wojv Kal rtov pLopiajv, 6p9a>$ av 
/^rjfxoKptros Xeyoc <f>alverai yap ovtojs viroXafielv. 
<f>rjoi yodv rtavrl SrjXov etvai olov ri rrjv [xop^rjv 
eariv 6 avdpojTTOs, ojs ovros avrov ra> re a^T^ari 
Kai rep yjpd}[iari yvojpljiov. Kairoi Kal 6 reOvetbs 

35 e\ei rrjv avrrjv rod uyrqixaros {JLop^rjv, dXX* ofiajs 
ovk ear iv avdpumos. en 8° dhvvarov elvai X € ^P a 
OTTOiOodv SiaKeijjLevrjv, olov xaXKijv rj ^vXlvrjv, TrXrjv 
641 a oixajvvfiojs, toGTTep rov yeypa\xp.evov larpov. ov ydp 
hwrjoerai Troielv to eavrrjs epyov, uioirep ovV avXol 
XlOlvol to eavrwv epyov 3 ouS' 6 yeypafifievos larpos. 


5 ptwv ovhev ert rwv tolovtojv eori, Xeyco 3' olov 
o^daXfxos, X € ty* XLav ovv dirXcbs eLprjrai, Kal tov 
avrov rpoTTOV worrep av el reKrojv Xeyot irepl ^eipdg 
ijvXivrjs. ovtojs ydp Kal oi <f>voioX6yoi ras yeveoeis 
Kal ras alrlas rod cr^T^iaros' Xeyovoiv, viro tlvojv 
yap ehrjixLovpyrjOrjcFav hwdfieajv; dAA' laws 6 fxev 
io reKTOJV epel ireXeKvv r) rpviravov, 6 8* depa Kal yrjv, 

See Diels, Fragmente 5 , 6S b 165. 
b i.e. the early writers on " Nature." 



any rate, the matter, if described, would be described 
as belonging to the concrete whole. For example, 
" a bed " is a certain form in certain matter, or, 
alternatively, certain matter that has a certain form ; 
so we should have to include its shape and the manner 
of its form in our description of it — because the 
" formal " nature is of more fundamental importance 
than the " material " nature. 

If, then, each animal and each of its parts is what it 
is in virtue of its shape and its colour, what Demo- 
critus says will be correct, since that was apparently 
his view, if one understands him aright when he says 
that it is evident to everyone what " man" is like as 
touching, his shape, for it is by his- shape and his 
colour that a man may be told.* v ; Now a corpse has 
the same shape and fashion as a living body ; and 
yet it is not a man. Again, a hand constituted in 
any and every manner, e.g., a bronze or wooden 
one, is not a hand except in name ; and the same 
applies to a physician depicted on canvas, or a flute 
carved in stone. None of these can perform the 
functions appropriate~~to the things that bear those 
names. Likewise, the eye or the hand (or any other 
part) of a corpse is not really an eye or a hand. 
Democritus's statement, therefore, needs to be quali- 
fied, or a carpenter might as well claim that a hand 
made of wood really was a hand. The physiologers, 5 
however, when they describe the formation and the 
causes of the shape of animal bodies, talk in this 
selfsame vein. Suppose we ask the carver " By what 
agency was this hand fashioned ? " Perhaps his 
answer will be *' By my axe " or *' By my auger," 
just as if we ask the physiologer " By what agency 
was this body fashioned ? "he will say " By air " and 



TrXrjv fieXriov 6 tcktcov ov ydp LKavov eorai avTw 


to i±kv KoiXov iyevero to Se tTTLireoov, dXXi Slotl 
ttjv 7rXt]yr]v €7toit}g<ito tololvttjv, Kal tIvos eveKa, 
ipel ttjv air lav, ottojs Toiovoe rj tolovoc 7totI ttjv 
fiop<f)r]V yivr\Tai* 
15 ArjXov toIvvv otl ovk opOcos XtyovGL, Kal OTL 

XtKTeOV (1)9 TOLOVTOV TO ^LOOV, Kal 77601 CKtlvOV Kal 

Kal 7Tepl tov e'loovs rrjs KXlvrjs. 

El $7] TOVTO €GTL ^f^ 1 ? V ^ V XV ? P^P ? V a ' veV 

ipvx'rjs (a7T€X9ovG7)s yovv ovkgtl £a>oV €gtlv, ouSe 
20 to)V \xopltov ovokv to avTO AeiVeTCu, 7tXt]v tw 
Gyy\\xarL \xqvov, KaOdnep to. fivOevo/ieva XidovoBaL), 

€L OTj TaVTa OVTOJS, TOV <f>VGLKOV 7T€pl l/jVX^jS O.V €L7] 

XiyeLV Kal eiSeVai, Kal el firj iraGiqs, KaT* ai)To 

7} aVTO TOVTO TO [JLOpLOV, Kal 77601 TO)V OVfXp€prj- 

Kal Trjs <f>vG€OJS St^cus" Xeyofjcevrfs Kal ovgtjs, Trjs 
[lev d)£ vXrjs, Trjs S* d>S ovGlas' Kal cgtlv avTrj Kal 
cos r) KLvovGa Kal (hs to TeXos' tolovtov oe TOV L^CpOV 

1 iKaarov Peck : eKaarov vulg. 

a Or, " reason " ; see Introduction, p. 24. 
b See above, 640 b 26. 
e " Soul " : see Introduction, pp. 34 ff. 
* Or '* motive." 



" By earth." But of the two the craftsman will give 
a better answer, because he will not feel it is sufficient 
to say merely that a cavity was created here, or a 
level surface there, by a blow from his tool. He will 
state the cause a on account of which, and the purpose 
for the sake of which, he made the strokes he did ; 
and that will be, in order that the wood might finally 
be formed into this or that shape. 

It must now be evident that the statements of the 
physiologers are unsatisfactory. We have to state 
how the animal is characterized, i.e., what is the 
essence and character of the animal itself, as well as 
describing each of its parts ; just as with the bed we 
have to state its Form. b 

Now it may be that the Form of any living creature 
is Soul, c or some part of Soul, or something that in- 
volves Soul. At any rate, when its Soul is gone, it 
is no longer a living creature, and none of its parts 
remains the same, except only in shape, just like the 
animals in the story that were turned into stone. 
If, then, this is really so, it is the business of the 
student of Natural science to inform himself con- 
cerning Soul, and to treat of it in his exposition ; 
not, perhaps, in its entirety, but of that special part 
of it which causes the living creature to be such as it 
is. He must say what Soul, or that special part of 
Soul, is ; and when he has said what its essence is, 
he must treat of the attributes which are attached 
to an essence of that character. This is especially 
necessary, because the term " nature " is used — 
rightly — in two senses: (a) meaning " matter," and 
(6) meaning " essence " (the latter including both 
the " Efficient " d Cause and the " End It is, of 
course, in this latter sense that the entire Soul or 



641 a t ^ ^ v ^ 

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kXivt) Kal rpiirovs to £vXov Iutiv, otl Svvdjiei ravrd 

* A.iroprjG€L€ 8' av tls eiS" to vvv Xeydkv tTufiXiijjas , 
TTorepov 7T€pl Trdarjs tftvxrjs 4 >vaLK V s T ° 

35 €L7T€LV T} 77601 TLVOS. 1 €L ydp 7T€pl TTacrrjS, OvSefJLLa 

AeiWrcu 7rapd rrjv cf>vcnKTjv ^TTiOTr\\vqv <f>iXooo(f)la. 
641 b 6 yap vov$ rwv vorjTOJVj ware rrepl TrdvTOJV rj 
(J)VGLktj yvcbois av elf]- rrjg ydp avrrjs rrepl vov Kal 
rod voTjrov Oecopfjaai, eirrep irpos d'AA^Aa, Kal rj 
avTTj Beiopia tcjv irpos aAA?jAa rravrajv, KaOdrrep 
Kal TTepl aiad-qoeojs Kal twv alaOrjrcjv. rj ovk k'ari 
5 7racra rj ^^X 7 ? KwrjcreoDS dpxtfy ovSe ra jxopia drravra, 
dXX* av^rjaews fiev orrep Kal iv rots' (f>vroLS y dX~ 
Xolojgccos 0€ to aloOrjTLKov, (f>opas S' CTZpOV TL Kal 
ov to vorjTLKov virdpx^ ydp rj <f>opd Kal iv irepois 
tcjv ^ojojVj Sidvoia S* ovSevt. SrjXov ovv cbs ov 

1 twos (jjLopiov} Rackham. 

° i.e. qualitative change, which is the " motion " proper 
to this part of the Soul. 



some part of it is the " nature " of a living creature. 
Hence on this score especially it should be the duty 
of the student of Natural science to deal with Soul 
in preference to matter, inasmuch as it is the Soul 
that enables the matter to "be the nature " of an 
animal (that is, potentially, in the same way as a piece 
of wood " is " a bed or a stool) rather than the matter 
which enables the Soul to do so. 

In view of what we have just said, one may well ask 
whether it is the business of Natural science to treat 
of Soul in its entirety or of some part of it only ; 
since if it must treat of Soul in its entirety (i.e. 
including intellect) there will be no room left 
for any other study beside Natural science — it will 
include even the objects that the intellect appre- 
hends. For consider : wherever there is a pair 
of interrelated things, such as sensation and the 
objects of sensation, it is the business of one 
science, and one only, to study them both. Now 
intellect and the objects of the intellect are 
such a pair ; hence, the same science will study 
both of them, which means that there will be 
nothing whatever left outside the purview of 
Natural science. All the same, it may be that 
it is neither Soul in its entirety that is the 
source of motion, nor yet all its parts taken 
together ; it may be that one part of Soul, (a), viz. 
that which plants have, is the source of growth ; 
another part, (6), the " sensory " part, is the source 
of change a ; and yet another part, (c), the source 
of locomotion. That even this last cannot be the 
intellectual part is proved, because animals other 
than man have the power of locomotion, although 
none of them has intellect. I take it, then, as evident 



tb f x ^ x 

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jiaoiv dXArj ris dpXl KC " atria roiavrr], rjv k'xofxev 

15 KaOdrrep to depfiov Kal to i/jvxpov Ik tov ttclvtos. 
Sid fxaXXov ethcos tov ovpavov yeyevrjodai vrro 
tololvttjs cut las, el yeyove, Kal elvai Sid TOiavT7)v 
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fievov Kal to ajpiojievov ttoXv fiaXXov ^airerat iv 

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cf>alv€Tai. iravTaxov he Xeyofxev rdSe rouS' eveKa., 
25 7tov av <f>alvr)TaL TeXos Tt rrpos o r) klvtjols nepalvei 
fjLrjSevos eyiTTohl^ovTOS . touTe elvai $>avepov oti eon 
tl tolovtov, o Sr) Kal KaXovpiev (frvcnv ov yap hi) 
6 tl eTV)(ev e£ Ikolutov ylveTai arrepfJiaTOs, aXXd 
ToSe iK Tovoe, ovoe anepfia to tu^ov €k tov tv- 

a With this passage cf Plato, Phihbus 29-30. 
6 Cf Samuel Butler, Life and Habit, p. 134, " A hen is 
only an egg's way of making another egg." 



that we need not concern ourselves with Soul in its 
entirety ; because it is not Soul in its entirety that is 
an animal's " nature," but some part or parts of it. 

Further, no abstraction can be studied bv Natural 
science, because whatever Nature makes she makes 
to serve some purpose ; for it is evident that, even 
as art is present in the objects produced by art, so in 
things themselves there is some principle or cause of 
a like sort, which came to us from the universe around 
us, just as our material constituents (the hot, the 
cold, etc.) did. a Wherefore there is better reason for 
holding that the Heaven was brought into being by 
some such cause — if we may assume that it came 
into being at all — and that through that cause it 
continues to be, than for holding the same about the 
mortal things it contains — the animals ; at any rate, 
there is much clearer evidence of definite ordering 
in the heavenly bodies than there is in us ; for what 
is mortal bears the marks of change and chance. 
Nevertheless, there are those who affirm that, while 
every living creature has been brought into being 
by Nature and remains in being thereby, the heaven 
in all its glory was constructed by mere chance 
and came to be spontaneously, although there is no 
evidence of chance or disorder in it. And whenever 
there is evidently an End towards which a motion 
goes forward unless something stands in its way, then 
we always assert that the motion has the End for its 
purpose. From this it is evident that something of 
the kind really exists — that, in fact, which we call 
" Nature," because in fact we do not find any chance 
creature being formed from a particular seed, but A 
comes from a, and B from 6 ; nor does any chance 
seed come from any chance individual. 6 Therefore 



641 b 

Xovtos GwpLaro$. apXV ^P a ^at rroi-qriKov rod e£ 
30 avrov to {e£ ov to) 1 GTrepfia. <f>vo€L yap ravra- 

7TpOT€pOV TO OV TO G7T€pfJLOL * y€V€GlS pi€V ydp TO 
G7T€p[jLGL 3 OVOLd TO TeXoS . dpi(j)oXv 8' €Tt 7T/)0- 

repoi'y d</>' o5 eort to G7T€p{ia, €gtl yap TO 
GTrepjxa St^cD?, e£ ou T6 /cat oi5* kcu ydo d</>' o5 


o eGrai i£ avrov, olov opecus, rpouov 8' ov rov 
avrov y dAA' tKaripov rov elprffievov. €tl 8e SwdfieL 

642 a to oWpjua* ovvapiis 8' d>s ex^L irpos ivreXex^Lav 


tcrty apa ov amcu auTat, to u ov eveKa Kai 
to i£ avdyKrjs' 7roXXd ydp ylv€rai s on dvdyKrj. 
igcds 8' av ri$ a7TOprjG€L€ irolav XiyovGiv dvdyKrjv 
6 ot Xeyovres i£ dvdyKTjs' raw fiev yap Svo rpo-ncov 
ovSerepov olov 0* V7rdpx€tv ra>v Stajoto/xeVajy iv toi? 
Kara <f>iXoGO(f)Lav. €gtl 8' ev ye tol$ k'xovoi yivtoiv 
rj rpCrrj- Xeyofiev ydp rrjv rpo(j)r}V dvayKalov ri /car' 
ovSerepov tovtojv rtbv rpoiraiVy dAA' on ovx olov r 
dvev ravrrjs etvai. rovro 8' IgtIv WGrrep i£ vtto- 
10 QeGea)$- wGrrep yap iirel Set cr^t^etv rep 7T€XeK€L s 
dvdyKTj Gt<Xr)pdv etvai, el 8e GKXrjpov, x a ^ K °vv r] 

1 <e| ov ro> supple\n, 2 secutus. 

a There is a reference here, which is not apparent in the 
English version, to the etymological connexion between <j>vai$ 
(nature) and faeadai (to grow). Cf. Met. 1014 b 16 ff. 

6 Viz. actuality is prior to potentiality. 

c These treatises are referred to again in the Politics 
(1282 b 19) and in the Eudemian Ethics (1217 b 23). The 
two modes of necessity seem to be (1) " absolute " necessity 
(mentioned here), and (2) " coercive " necessity (see Met. 


the individual from which the seed comes is the 
source and the efficient agent of that which comes 
out of the seed. The reason is, that these things 
are so arranged by Nature ; at any rate, the offspring 
grows a out of the seed. Nevertheless, logically 
prior to the seed stands that of which it is the seed, 
because the End is an actual thing, and the seed is 
but a formative process. But further, prior to both 
of them stands the creature out of which the seed 
comes. (Note that a seed is the seed " of " some- 
thing in two senses — two quite distinct senses : it 
is the seed " of" that out of which it came — e.g. a 
horse — as well as " of " that which will arise out of 
itself— e.g. a mule). Again, the seed is something 
by potentiality, and we know what is the relation of 
potentiality to actuality. 5 

We have, then, these two causes before us, to wit, 
the " Final " cause, and also Necessity, for many 
things come into being owing to Necessity. Per- 
haps one might ask which " Necessity " is meant 
when it is specified as a cause, since here it can be 
neither of the two modes which are defined in 
the treatises written in the philosophical manner. 
There is, however, a third mode of Necessity : it 
is seen in the things that pass through a process of 
formation ; as when we say that nourishment is 
necessary, we mean " necessary " in neither of 
the former two modes, but we mean that without 
nourishment no animal can be. This is, practically, 
" conditional " Necessity. Take an illustration : A 
hatchet, in order to split wood, must, of necessity, be 
hard ; if so, then it must, of necessity, be made of 

1015 a 20 ff.). The third he has referred to already at 
639 b 2.5, viz. '* conditional " necessity, bee pp. 21 f. 



athrjpovv, ovtoj /cat eVet to oxo/xa opyavov (eve/ca 
twos yap €kclgtov rcov pLopiwv s ofJioitos oe /cat TO 
oAov), dvdyKTj dpa roiovhl elvai /cat €K tolojvSi s ei 


"On fiev ovv hvo rpoiTOL rrjs atrlag, /cat Set 
15 Xeyovras Tvyxdveiv juaAtara fxev afx^olv, el he in;, 
7T€ipda0aL ye iroielv tovto, hfjXov, 1 /cat otl iravres ot 
tovto fxrj XeyovTes ovhev cog elueiv irepX <f>vGews 
Xeyovaiv dpx^} ydp rj <f>VGis uaAAov rrjs vXrjs. 
(ivcaxov he ttov avrfj /cat ^[nrehoKXrjs irepiTTiTTTei, 
dydfievos vtt* avrfjs rrjs dXrjOelas, /cat rrjv ovuiav /cat 
20 rrjv (f)VGLV dvay/ca£eTat (f>dvaL rov Adyov etvat, otov 


gtolx^lojv Xeyei avro ovre hvo rj rpla ovre ndvra, 
dXXd Adyov ttJ? /xtfeoj? avrcbv. orjXov rolvvv ore 
/cat rj adp£ tov avrov rpoirov eGTi 3 /cat rcov dXXcov 


25 iXOetv rovg TTpoyeveGrepovs errl tov rporrov tovtov, 
on to Tt 17V elvai /cat to dotaacrflat rrjv ovGiav ovk 
rjv, dXX* rji/jaro fiev A^ud/cptTO? 7Tpd)Tos, ojs" ovk 
dvayKCLiov he rfj (f>vGLKrj 9ea>pta ) dAA' eKcfiepofjievos 
V7T* avrov rov TTpdyfiaro^' errl ^wKparovs he tovto 
liev rjv^-qOrj, to he ^rjTeXv ra nepl j>VGea)s eXrjtje, 

1 sic Ogle : el Se ^.77, BfjAov ye 7T€ipao$au ttouuv vulg. 
See Diels, Fragmented, 31 a 78. 

b ** Element " : this term is normally used to denote the 
four substances, earth, water, air, fire. 

c This is probably a reference to Democritus's opposition 
to the theories of Protagoras, who held that ** what appears 



bronze or of iron. Now the body, like the hatchet, 
is an instrument ; as well the whole body as each 
of its parts has a purpose, for the sake of which it 
is ; the body must therefore, of necessity, be such 
and such, and made of such and such materials, 
if that purpose is to be realized. 

It is, therefore, evident that of Causation there are 
two modes ; and that in our treatise both of them 
must be described, or at least an attempt must be 
made to describe them ; and that those who fail 
herein tell us practically nothing of any value about 
" Nature/' for a thing's " nature " is much more a 
first principle (or " Cause ") than it is matter. (In- 
deed, in some places even Empedocles, being led 
and guided by Truth herself, stumbles upon this, 
and is forced to assert that it is the logos which is a 
thing's essence or nature. a For instance, when he is 
explaining what Bone is, he says not that it is any one 
of the Elements, 6 or any two, or three, or even all of 
them, but that it is " the logos of the mixture " of 
the Elements. And it is clear that he would explain 
in the same way what Flesh and each of such parts is. 
Now the reason why earlier thinkers did not arrive 
at this method of procedure was that in their time 
there was no notion of " essence " and no way of 
defining " being." The first to touch upon it was 
Democritus ; and he did so, not because he thought 
it necessary for the study of Nature, but because he 
was carried away by the subject in hand and could 
not avoid it. c In Socrates' time an advance was 
made so far as the method was concerned ; but at 
that time philosophers gave up the study of Nature 

to be to you, is for you." Protagoras had emphasized the 
validity of sense-data ; Democritus denied it. 



642a » ^ x > > * » * ^ 

30 irpos oe rrjv xP'*} (Jl l Ji0V aper 7 ] v Kat T ^i v rroAirtKTjv 
aTre/cAivay ot ^)iXoao(f)ovvres .) 

&€LKT€OV 8' OVTWS, OLOV OTl €(JTl fl€V TJ dvaTTVOT] 

rovhl -^dpiVy rovro he ylverai Std rcESe e£ dvdyKTjs* 
rj 8' dvdyKTj ore fiev orjfiaivei on el eKetvo carat 
to ov eveKa, ravra dvdyKTj iarlv (owtcos') 1 e^eiv, 
35 ore S' OTt eanv ovrws k'xpvra Kal rrecftvKora' to 
depfiov yap dvayKalov e^tivat Kal rrdXiv eloievai 
dvrtKpovov, rov 8' depa elapelv rovro S' -37877 
642 b dvayKalov eariv, rov evros he Oepfiov dvriKorrrovros 
iv rfj iftv^et rov OvpaOev depos 77 etaohos 2 Kal rj 
e^ooos. 6 {lev ovv rporros ovros 6 rrjs [leOohov, 
Kal Trepl (hv Set Xafieiv rds alrlas, ravra Kal 
rotavrd eariv. 
5 II. Aafifidvovoi 8' evtoi to KaO* eKaarov } 8t- 
aipovfievoc to yevos els hvo hia<f>opds. rovro 8' earl 
rfj fxev ov pdoiov y rfj he dhvvarov. evtajv yap k'arai 

1 ovrws supplevi. 
2 r) etooSos om. pr. E. 

a " Goodness," or " virtue," is one of the chief topics 
discussed by Socrates in the Platonic dialogues. Cf. 
Aristotle, Met. 9S7 b 1, " Socrates busied himself about moral 
matters, but did not concern himself at all with Nature as 
a whole." 

b I have not attempted, except by one insertion, to straigh- 
ten out the text of this confused account, which looks 
like a displaced note intended for the paragraph above 
(ending " realized," p. 77). If it is to remain in the text, it 
would follow at that place (after 642 a 13) least awkwardly. 
For a more lucid account of the process of Respiration see 
De resp. 480 a 16-b 0. 

c This \s usually held to include Plato, on the ground that 


and turned to the practical subject of " goodness," a 
and to political science.) 

& Here is an example of the method of exposition. 
We point out that although Respiration takes place 
for such and such a purpose, any one stage of the 
process follows upon the others by necessity. Neces- 
sity means sometimes (a) that if this or that is to 
be the final Cause and purpose, then such and such 
things must be so ; but sometimes it means (6) that 
things are as they are owing to their very nature, as 
the following shows : It is necessary that the hot 
substance should go out and come in again as it 
offers resistance, and that the air should flow in — 
that is obviously necessary. And the hot substance 
within, as the cooling is produced, offers resistance, 
and this brings about the entrance of the air from 
without and also its exit. This example shows how 
the method works and also illustrates the sort of 
things whose causes we have to discover. 

II. Now some writers c endeavour to arrive at the 
ultimate and particular species by the process of 
dividing the group (genus) into two differentiae* 
This is a method which is in some respects difficult 
and in other respects impossible. For example : 

the method of dichotomy is used in the Sophist and Pol it kits. 
But the method can hardly be said to be seriously applied 
to the classification of animals in the Pol it kits, and in the 
Sophist it is introduced partly in a humorous way, partly 
to lead up to the explanation of to firj 6v (not-being: I. Either 
Aristotle has mistaken the purpose of the method (as he 
has at An. Pr. 46 a 31 ff.) or (much more probably) he is 
referring to some other writer's detailed application of it- 
See e.g. Stenzel in Pauly^Yissouxi. s.v. Speusippus. 

d Each stage of the division gives two differentiae, which 
are treated as " genera " for the next stage of the division, 
and so on. 



Stacf)Opd i±La fJLOvr} } ra 8' dXXa irepiepya, olov vno- 
ttovv, Slttovv, (jx^ottovv 1 ' (xvTTj yap fiovf] Kvpla. 

10 el he {JLTj, ravrov TroXXaKLS dvayKalov Xeyeiv. en 
he 7Tpo<jr)K€L fir} hiaoirav eKaurov yevos, olov rovs 
6'pviQas rovs pikv ev rfjhe rovs 8' ev dXAr) hiaipeoei, 
KaQduep e^ovcnv al yeypa\i\xevai hiaipeoeis* eKei 
ydp rovs fiev fiera rcbv evvhpajv ovp-fialvei St- 
-QprjaOai, rovs 8' ev dXXtp yevei, (ravrrj jiev ouv rfj 

15 ofAOLOTTjTi dpvis ovofAOL Kelrat, erepa. 8' lx@vs m a'AAat 
8' elalv dvdovvfxoij olov to evatfiov Kal to dvatfiov 
eft eKareptp ydp tovtlqv ov Keirai ev ovofia.) elirep 
ovv fjLTjSev rcbv djioyevtbv SiauTraoreov, rj els 8uo 
SidLpeois fjidrouos av etr\ % ovrco ydp Siaipovvrag 
dvayKalov yu^pi^eiv Kal hiaouav rcbv ttoXvttoSojv 
ydp eon ra fiev ev rols ire^ols ra 8' ev rolg 

20 ivvSpois. 

III. "Eti tTTeprjaei p.ev dvayKalov hcaipelv Kal 
hiaipovuiv ol hi^oTopLOVvres . ovk eon he Sta^opa 

1 avow post ox^ottovv vulg., del. Ogle ; fortasse [a-Trrepov] 
scribendum (cf. An. Post. 92 a 1, Met. 1037 b 34). 

° Other groups will get broken up under several lines of 
division, as Aristotle goes on to say, and he repeats this at 
643 b 14, where he adds that " contrary " groups will get 
lumped together under a single line (and " contrariety is 
maximum * difference,' " see Met. 105.5 a 5 if., cf. 1018 a 30). 

b Aristotle holds that one is not enough ; see 643 b 9 fF. 
and 29 ff. 



(a) Some a groups will get only one differentia? the 
rest of the terms being superfluous extras, as in the 
example : footed, two-footed, cloven-footed d — since 
this last one is the only independently valid differentia. 
Otherwise the same thing e must of necessity be 
repeated many times over. 

(6) Again, it is a mistake to break up a group, as 
for instance the group Birds, by putting some birds 
in one division and some in another, as has been clone 
in the divisions made by certain writers : in these 
some birds are put in with the water-creatures, and 
others in another class. (These two groups, each 
possessing its own set of characteristics, happen to 
have regular names — Birds, Fishes — but there are 
other groups which have not, e.g. the " blooded " 
and " bloodless " groups : there is no one regular 
name for either of these.) If, then, it is a mistake 
to break up any group of kindred creatures, the 
method of division into two will be pointless, because 
those who so divide are compelled to separate them 
and break them up, some of the many-footed animals 
being among the land-animals and others among the 

III. (c) Again, this method of twofold division 
makes it necessary to introduce privative terms, and 
those who adopt it aetually do this. But a privation, as 

e i.e. all terms except the final one can be dispensed with, 
because none of them constitutes an independent (Kvpla) 
differentia ; one line of division yields one valid differentia 
and no more (cf. 644 a 2-10). 

d Cf 644 a 5 and Met. 103S a 32. 

« In this case, " -footed " (cf. Met. 103S a 19 if.). But 
Aristotle does not explain how Show is '* superfluous." 



642 b / ~ , , wo. ? 

areprjaews fj oreprjots' dhvvarov yap eiorj eivai rov 

fir) ovros, olov rrjs a7TOolas r) rod drrrepov axmep 
7Trept6aea>s Kal 7roSd)v Set 8<e rrjs KaQoXov 8ia- 

25 <f>opas 61877 eivai- el yap fir) earac, Sia rl av elf] 
rcov KaQoXov Kal ov rcov Ka6* eKaarov; rcov oe 
OLa<f>optov at fiev KaQoXov elal Kal e'xovaiv e&r\ y 
olov TTTeporrjs' to jiev yap aoyiGTOv to V ecr^i- 
Ofievov earl irrepov. Kal TroSorrjs toaavrcos r) [xev 
rroXvax^rjs, r) 8e Sta^tS^j, olov ra St^aAa, r) 8' 

30 aaxtSrjs Kal dhialperos y olov ra fJLcbvvx&- x a ^ €7T ° v 
fiev ovv StaXafieLV Kal els rotavras $ia<f>opds cov 
eonv et8r) } cooQ* oriovv ^wov ev ravrais virapyew 
Kal fjirj ev rrXecoGt ravrov (olov irrepcorov Kal 
dnrepov eon yap dficf>co ravrov, olov fivpfirj^ Kal 

35 XafATTvpls Kal erepd nva) } uavrcov 8e x a ^ €7T ^ )Tarov 
rj dSvvarov els rag avrtKetfJievas } dvayKalov yap 
rcov KaQ* eKaarov vnapx^tv rivl rcov oiatf>opcov 

643 a iKaorrjv, ware Kal rrjv dvrcKetfievqv . el oe per) 

cVSe^erat rot? etSec oiac^epovaiv virapx^w ethos n 
rrjs ovaias aro\xov Kal ev } dAA' del otacf>opdv e£et 
2 (olov opvis dvOpcoirov — rj St7roSia yap aXXrj Kal 
otdtf>opos' Kav el evatfia, to atfia oidtf>opov y rj ovSev 
5 rrjs ovaias ro alp.a Oereov) — el 8' ovrtos earlv, r) 

1 raj avTLK€ifi€vas Peck : ra dvriKtliieva Titze : rd dvaifia 
vulg. : ra eVavrta Ogle : ra aro/xa Prantl. 

2 11. 3-6 interpunctionem correxi. 

° I have not attempted to keep a consistent translation for 
irrepov, as Aristotle applies this term to "feathers " and to 
'* wings " (of insects). 


privation, can admit no differentiation ; there cannot 
be species of what is not there at all, e.g. of " foot- 
less " or " featherless," a as there can be of " footed " 
and " feathered " ; and a generic differentia must 
contain species, else it is specific not generic. How- 
ever, some of the differentiae are truly generic and 
contain species, for instance " feathered " (some 
feathers are barbed, some unbarbed) ; and likewise 
" footed " (some feet are " many- cloven," some 
" twy-cloven," as in the animals with bifid hoofs, 
and some (t uncloven " or " undivided," as in the 
animals with solid hoofs). Now it is difficult enough 
to arrange the various animals under such lines of 
differentiation as these, which after all do contain 
species, in such a way that every animal is included in 
them, but not the same animal in more than one of 
them (e.g. when an animal is both winged and wing- 
less, as ants, glow-worms, and some other creatures 
are) ; but it is excessively difficult and in fact im- 
possible to arrange them under the opposite lines of 
differentiation. Every differentia must, of course, be- 
long to some species ; and this statement will apply 
to the negative differentiae as well as to the positive. 
Now it is impossible for any essential characteristic 
to belong to animals that are specifically different and 
at the same time to be itself one and indivisible & : it 
will always admit of differentiation. (For example, 
Man and Bird are both two-footed, but this essential 
characteristic is not the same in both : it is differenti- 
ated. And if they are both " blooded," the blood 
must be different, or else it cannot be reckoned as 
part of their essence.) If that is so, then, the one 

b As the privative characteristic would have to be. 
« See below, 693 b2ff. 



643 a 

fjLLa $ta<f>opd hvolv vTrdp^et- 1 el 8e rovro, hrjXov 
otl dhvvarov GTeprjoiv etvai hia<f)opdv. 

"Ecrovrai 8' al 8ta(f>opal taat tols dro^OLg Repots, 
eiirep drojia re ravra Kal al Sta^opal arojioi, 
Koivr) Se fjaj lor iv. (el 8' evoex €rai virdpx^ 2 Kal 
io Kotvrjv, drofjiov Se, orjXov otl Kara ye rrjv kolvtjv ev 
roj avra> Iotlv ere pa ovra ra> etoei £a>a. wot 
dvayKatov, el lolol al 8ta^»opat els as anavra 

€{177 L7TT€L TO. d,TO[JLa f [JLTjOeflLaV aVTWV €LVai KOLVrjV 

el he fii], erepa ovra els ttjv avrrjv jSaSietrat.) Set 
8* ovre to avro Kal aTOpiov els erepav Kal erepav 

16 levai hia<f)opav rcov oLTjprjfjLevwv, ovt els tt)v avTtjv 
erepa, Kal diravTa els raura?. (f>avep6v tolvvv otl 
ovk eon XafieZv rd drofia etSrj cbs StaLpovvTaL ol els 
ouo oiatpovvTes ra £a)a rj Kal dXXo otlovv yevos. 
Kal yap KaT eKelvovs dvayKalov loas rds eo^dras 
elvai $t,a(f)Opas tols ^cools ttclol to?s dropois to> 

2oe?Sei. ovtos yap Tovhe tlvos yevovSt ov oiacfropal 
TTpcorat ra (XevKa Kal ra XevKa, tovtcov 8' 

eKarepov dXXai, Kal ovtcos els to rrp6oa> ecus tcov 
dropcov, al TeXevTatai Terrapes eoovTai rf dXXo tl 

1 11. 3-6 interpunctionem correxi. 

2 firj v7rdpx€Lv vulg. : corr. Titze. 

3 supplevit Cornford. 

a Because it cannot fulfil the condition of admitting 
differentiation. At whatever stage of the division it comes 
(unless at the very end), the privative term will cover at least 
two species, and therefore at the next stage the dichotomists 
will have to divide it — illegitimately, as Aristotle maintains. 


differentia will belong to two species. And if so, 
it is clear that a privative cannot be a valid 

(d) Xow assuming that each species is indivisible : if 
each differentia also is indivisible, and none is common 
to more species than one, then the number of differ- 
entiae will be equal to the number of species. (Suppos- 
ing it were possible to have a differentia which though 
indivisible was common ; clearly, in that case, animals 
which differed in species would Ije in the same division 
in virtue of that common differentia. Therefore, if the 
differentiae under which the indivisible and ultimate 
species fall are to be proper and private to each 
one, it is necessary that no differentia be common ; 
otherwise, species which are actually different will 
come under one and the selfsame differentia.) And 
we may not place one and the same indivisible 
species under two or three of the lines of differentia- 
tion given by the divisions ; nor may we include 
different species under one and the same line of 
differentiation. Yet each species must be placed 
under the lines of differentiation available. It is 
evident from this that it is impossible to arrive at the 
indivisible species either of animals or of any other 
group by the method of twofold division as these 
people practise it, for even on their shoving the 
number of ultimate differentiae must of necessity be 
equal to the total number of indivisible species of 
animals. Thus, suppose we have some particular 
group of creatures whose prime differentiae are 
" pale " and " not pale " : by that method these 
two will eaeh give two other differentiae, and so 
forth, until in the end the indivisible differentiae are 
reached : these last ones will be either four in 



643a ^ s / 

-\rj9og tcov a<f> evos St—Aacrta^o/xeVtov* roaavra oe 

Kal ri eiSrj. 

("Kan §' rj 8ia^>opa rfj vXrj to efSo?. 1 oure 
25 yap avev vXrj? ovoev ^coov \iopiov } ovre fiovrj rj 
vXrj- ov yap Travrcos ^X ov <7C ^i Lta ecrrat £tpov, ovSe 
tcov pLoplcov ovSev y ooarrep TroXXaKts eLprqr ai.) 

w Eti otaipeiv %pr} rots* ev rfj ova la Kal pLrj TOtg 
ovufiefiirjKOGL KaQ* avro, olov el ns ra ayr\\xara 
OLatpoLT], Stl ra. [lev ovulv 6p6ai$ i eras' e^et Tas* 
30 ycovlas, ra Be TrXeloaw avfifiefirjKos yap tl tco 
rpLycovco to Bvolv dpdaZs teas' ^X €LV T ^ yojvlas. 

v Ert toIs avTLK€LfievoLS oiaipeiv (Set)/ Bid^opa 
yap aXXrjXois ravr lk€ I fieva, olov XevKOTTjg Kal pie- 
Xavla Kal evQvTfjs Kal KapLrrvXoT-qs . edv ovv darrepa 

Sid(pCpa fj } TO) aVTLK€Lfl€VOJ BiaipeTeOVy Kal fJLT] TO 

35 [lev vevaei to Be xp c l ) l JLarL - rrpos Be tovtols, ra y 
eiMifjvxa Totb kolvoTs epyoig tov ocofiaTOs Kal Trjs 
643 b fox?}?, olov Kal ev Taig p-qdelaais vvv TropevTLKa Kal 
TTTTjvd — eoTi yap Tiva yhrq oh ap,<j>w vrrapxet Kal 
eoTi TTTTjvd Kal a7TTepa } KaOdrrep to tcov (jLvpfXTjKojv 

1 sic Y : to d6os ev rfj v\r) vulg. 
2 (Set) supplevi. 

a His point is that it is nonsensical to suppose that this 
numerical correspondence is bound to occur. 
b As at 641 a IS ff. 
c See Met. 1025 a 30. 

d These are enumerated in Be sensu, 436 a 7 ff., and Aris- 
totle seems here to be thinking of them as grouped together 
under the several faculties — nutritive, appetitive, sensory, 


number, or some higher value of 2" ; and there will 
be an identical number of species. 

(The species is the differentia in the Matter. There 
is no animal part which exists without matter ; nor 
on the other hand is there any which is matter only, 
for body in any and every condition cannot make an 
animal or any part of an animal, as I have often 
pointed out. 5 ) 

(e) Again, the division ought to be made according 
to points that belong to the Essence of a thins: and 
not according to its essential (inseparable) attributes. 
For instance, in making divisions of geometrical 
figures, it M-ould be wrong to divide them into those 
whose angles are together equal to two right angles 
and those whose angles are together greater than two 
right angles ; because it is only an attribute of the 
triangle that its angles are together equal to two 
right angles. 

(f) Again, division should be by " opposites," 
opposites being mutually " different." e.g. pale and 
dark, straight and curved. Therefore, provided the 
two terms are truly " different." division should be 
bv means of opposites, and should not characterize 
one side by ability to swim and the other side by 
some colour. And besides this, division of living 
creatures, at any rate, by the functions which are 
common functions of body and soul. d such as we 
actuallv rind done in the divisions mentioned above, 
where animals are divided into " walkers " and 
" fliers " — for there are some groups, such as that of 
the Ants, which have both attributes, being both 

locomotive, and thought (see De an. 414 a if.). His point 
is that the correct way to divide and classify animals is rather 
bv bodilv characteristics, which is what he himself does. 



yevos — Kal toj dyplco Kal 1 rjfjLepu) <(ou Set) 2 Statpet- 
<j6ai ' (haavrcDs ydp dv So^ete ravra etSr} Siaipelv 

5 Trdvra ydp s ojs elirelv, oua r^xepa Kai aypia rvy- 
xdvei 6vra s olov dv6pa>7TOL } ittttoi, floes, Kvves ev rfj 
y lvSiKjj } ves 3 atyes s TTpoflara' qjv zkolotov, el fiev 
ojjLwvvjjiov, ov $LT)pr]TaL y^copiSy el Se ravra ev et'Set, 
ovx olov r elvai hia<j>opdv to dypiov Kal ro -qfiepov. 
*OAa>? S' oiToiaovv Sta</>opa 3 ^tta hiaipovvrt rovro 

10 ovjifialveiv dvayKalov. dXXd Set TreipaaOai Xafi- 
fidvetv Kard yevt] rd t l <ha 3 cLs vcfyrjyrjvd' ol 7roAAot 
Stoplaavres opviOos yevos Kal t^^uos". rovrcuv S' 
eKaurov voXXals djpLcrrai Sta^opats 1 , ov Kara rrjv 
St^orojLttW. ovrcx) fxev yap rjroc ro rrapdnav ovk 
ear i Xafielv (ro avro yap els rrXelovs ifiTrlrrrei 

is Siaipeaeis Kal rd ivavrla els rr)v avrr}v) J r) 
(jlovov &iacf)opd earatj /cat avrr] r\roi drrXrj rj eK 
avjxrrXoKrjs ro reXevralov eorai etSos. eav he fxrj 
Sia(j)opds Xafxfidvr] ris hia<f>opdv } 4 dvayKalov s woTrep 
avvSeafjLcp rdv Xoyov eva rroiovvras } ovra> Kal rrjv 
Sialpeoiv uvvex^} rroielv. Xeyoj S' olov ovpifialvei 

-0 rols hiatpovjxivois ro fiev drrrepov ro Se urepuyrov } 
Trrepwrov Se ro fiev rjjjLepov ro S' ayptov, rj ro fiev 

1 Kal EY : Kal rw vulg. 

2 supplevi. 

3 oiroiavovv Sia<f>opdv alii : oiroiaovv \ : Sta^opa vel Bta<f>opd 

4 $ta<f)opa A. ES : $ia<f)opav A. tt)s bia<f>opas P : Bi.a<f>opas A. 
§ia<f>opav Y ; tls Peck : r-qv vulg. 

a Cf. Plato, PoUticus, 264 a 1. 
b On this see Piatt, C.Q., 1909, iii. 241. 
c For Bta<f)opd in the sense of " bifurcation " cf. Met. 
1048 b 4, where he speaks of the two "parts " of a Lafopd. 
d i.e. with the preceding terms. See below, 644 a 5. 



" ringed " and '* wingless " — and by " wild " and 
" tame," is not permissible, for this similarly would 
appear to divide up species that are the same, since 
practically all the tame animals are also found as 
wild ones : e.g. Man, the horse, the ox, the dog (in 
India & ), swine, the goat, the sheep ; and if, in each 
of these groups, the wild and the tame bear the same 
name, as they do, there is no division between them, 
while if each group is specifically a unit, then it 
follows that " wild " and " tame " cannot make a 
valid differentiation. 

And generally, the same thing inevitably happens 
whatever one single line of differentiation is taken for 
the division. The proper course is to endeavour to 
take the animals according to their groups, fol- 
lowing the lead of the bulk of mankind, who have 
marked off the group of Birds and the group of Fishes. 
Each of these groups is marked off by many differentiae, 
not by means of dichotomy. By dichotomy (a) either 
these groups cannot be arrived at at all (because the 
same group falls under several divisions and contrary 
groups under the same division) or else there will be 
one differentia only, and this either singly or in 
combination d will constitute the ultimate species/ 
But (b) if they do not take the differentia of the differ- 
entia, they are forced to follow the example of 
those people who try to give unity to their prose by a 
free use of conjunctions : there is as little con- 
tinuity about their division. Here is an example 
to show what happens. Suppose they make the 
division into " wingless " and " winged," and then 
divide " winged " into *' tame " and " wild " or into 

• And this will never completely represent any actual 
group or species. See below, 6i4 a 6 ff. 



643 b ^ \ \ t x o x 

XevKov to Be fieXav ov yap oiacpopa rod rrrepajrov 
TO 7]fJL€pOV ovBe to XevKov, aXX erepas dp^i] 8ta- 
<j>opas' e/cet Be Kara ov[ifief$r]K6$ . 8to TroAAat? to 
eV evOeojs Biaipereov, axnrep Xeyofiev. /cat yap 

25 ovrojg p.ev at aTepTjaets- rroirjGOVGi Bia<f>opdv, ev Be 
rfj BixoTOjJLiq ov TTOirjcrovcnv, 

°Ori 8' ovk eV8ev6Tat tojv /ca0 5 eKaarov elBwv 
Xafifidveiv ovBev Biaipovui St'^a to yevos, woTrep 
rives dtrjOrjaav, /cat e/c Ta>v8e cf>avepov. 

'ABvvarov yap filav vrrdpxetv Biacf)Opdv rwv 

30 KaO* eKaarov Biaipereov, eav y ctTiAa Xajjifiavrj ns* 
idv re crvfj.TTeTrXeyjj.eva* [Xeyw Be dnXa [lev, eav yurj 
e'xj) Bia<f>opdv, olov rrjv ox^orroBiav, uvpiTTenXey- 
fieva Be, eav eXT)> °* ov T ° rroXv^x^Bes rrpos to 2 
a^t^o77ouv] 3 rovro yap rj awe^eta fSovXerai ra>v 
dno rod yevovs Kara rrjv Bialpeuiv Bia<f>opa)v d>s ev 

35 Tt to rrav ov, dXXd napd rrjv Xe£iv ovfJifSalvei So/cetV 
rrjv reXevraiav \xovr\v etvai Bia^opdv [olov to ttoXv- 

644 a o^tSe? rj to Blttovv, to 8' vttottovv /cat ttoXvttovv 

TrepUpya].* on 8' dBvvarov rrXelovs elvai roiavras, 
BrjXov del yap ftaBi^wv erri rrjv eaxdrrjv Bia<f>opdv 
d<pLKvelrai [dAA* ovk erri rrjv reXevraiav /cat to 
etSo?]' 5 avrrj 8* eariv r) to gx^ottovv jj.6vov, rj 
5 rracra r) avfiTrXe^Ls, eav BiaLpijrai avOpamos* olov 
el ns avvdelrj vttottovv, Blttovv, gx^^ottovv. el 8' 
r)v 6 avQpojTTOS gx^ottovv jjuovov, ovrws eylyver dv 
avrrj {t}) 7 p.ia Bia<f>opd. vvv 8' erreiBr) ovk eGriv t 

1 rt? Y : om. vulg. 2 -rrpos tw Piatt. 

3 seclusi. codices varia, ut videtur; sic Bekker. 
4 olov . . . irepUpya seclusi. 
5 aAA* . . . d&os seclusi. 
6 avOptonov vulg. 7 <t}> Ogle. 



" pale " and *' dark " : neither " tame " nor <£ pale " 
is a differentiation of " winged," but the beginning 
of another line of differentiation, and can come in 
here only by accident. Therefore, as I say, in dividing 
we must distinguish the one original group forthwith 
by numerous differentiae ; and then too the privative 
terms will make valid differentiae, which they will 
never do in the system of dichotomy. 

Here are further considerations to show that it is 
impossible to come at any of the particular species by 
the method of dividing the group into two. as some 
people have imagined. 

Ob'uously it is impossible that one single differentia 
is adequate for each of the particular species covered 
by the division, whether you adopt as your differentia 
the isolated term or the combination of terms a (for 
this is intended by the continuity of the series of 
differentiae throughout the division from the original 
group, to indicate that the whole is a unity ; but, in 
consequence of the form of the expression, the last 
one comes to be considered as the sole differentia). 
And it is evident that there cannot be more than one 
such differentia ; for the division proceeds steadily until 
it reaches the ultimate differentia, and — supposing the 
division is aiming at " Man "—this is either " cloven- 
footed " alone, or else the whole combination, e.g. 
if one combined " footed," " two-footed." " cloven- 
footed." b If Man were merely a cloven-footed 
animal, then this would be the one differentia, arrived 
at by the right method. But as he is not merely 

a i.e. the last term of any series, or all its terms together, 
as he goes on to say. Cf. 643 b 15 f. 

b This definition appears also in Met. 103T-103S. 




l a 

avdyKTj ttoXXcls elvai firj vito \ilav hiaipeoiv. dAAd 
jjLTjv rrXeiovs ye rod avrov ovk eaTiv vtto fiiav 

10 StxorojjLLav elvai, dXXa \xlav Kara \xiav reXevrdv. 
wore dhvvarov otlovv XafieTv tcjv kclQ* eKacrrov 
^coojv Scy^a hiaipovyiivovs . 

IV. 'A7TOprjG€i€ 8* av rts 1 8id tl ovk dvwOev evl 
ovofiarL ifiTTepiXafiovres dfia ev yevos djJLcjxx) irpoo- 
rjyopevaav oi dvOpamot, o irepieyei rd re evvSpa 

15 Kal rd 7Trrjvd tcov ^coojv eon yap evia nddr] 
Kotvd Kal tovtols [Kal rot? d'AAois" £ojois* arraaLv]. 1 
dAA* ojjlcos 6pdd>s SicopLaraL rovrov rov rpoirov. 
oaa [xev yap oiacfrepet twv yevcbv Ka6* v7repo)(r)v Kal 
to) jjl&XXov Kal rjrroVj 2 ravra vrre^evKTat evl yevei, 
oaa 8* eyei to dvdXoyov y -^wpts' Xeyw 8* olov opvis 

20 opviOos Staq^epet ra> jjl&XXov rj Ka9* VTrepoyrp (to 
[lev yap fiaKpoTrrepov to ce fipa)(V77Tepov) , Indues 
8' opviOos to> dvdXoyov (o yap eKetvcp 7Trep6v y 8a- 
Tepw Xeiris). tovto he iroieiv eirl iraaiv ov pdSiov 
rd yap noXXa £aia dvdXoyov rairro ireirovftev. 

'E77€t 8* ovolai fxev eloi rd ea^aia elSr], /caret 

25 he TavTa rd 3 to clSog d8id(f>opa {olov HajKpaTrjs, 
KopLcrKos), dvayKaZov rj rd KaOoXov vjrdpypvTa 

1 seclusi Ogle clocente. 
2 sic Rackham: to \loKKov Kal to (to om. Y) Jjttov vulg. 
3 Kara $e ravTa ra Peck : ravra $e /caret vulg. 

a This paragraph has been corrupted by confusing inter- 
polations, which I have bracketed in the Greek text and 
omitted in the translation. With this passage cf. Met. 
1037 b 27—1033 a 30. 

b On this point see D'Arcy W. Thompson, Growth and 
Form, esp. ch. 17, and the same author's paper Excess 
arid Defect ; or The Little More and the Little L<ess, in 
Mind* xxxviii. (N.S.) 149, pp. 13-55. See also infra, 
661 b 28 ff M 692 b 3 ff. ; and Introduction, p. 39. 



that, it is necessary that there should be many 
differentiae, not under one line of division. And yet 
there cannot be more than one differentia for the same 
thing under one line of dichotomy : one line must end 
in one differentia. So it is impossible for those who 
follow the method of twofold division to arrive at any 
of the particular animals. a 

IV. Some may find it puzzling that general usage 
has not combined the water-animals and the feathered 
animals into one higher group, and adopted one name 
to cover both, seeing that in fact these two groups 
have certain features in common. The answer is that 
in spite of this the present grouping is the right one ; 
because while groups that differ only " by excess " 
(that is, " by the more and less " 6 ) are placed 
together in one group, those which differ so much 
that their characteristics can merely be called ana- 
logous are placed in separate groups. As an illus- 
tration : (a) one bird differs from another bird " by 
the more," or " by excess " : one bird's feathers 
are long, another's are short ; whereas (b) the 
difference between a Bird and a Fish is greater, 
and their correspondence is only by analogy : a fish 
has no feathers at all, but scales, which correspond 
to them. It is not easy to do this in all cases, for 
the corresponding analogous parts of most groups of 
animals are identical. 

Now since the ultimate species are " real things," c Method* 
while within them are individuals which do not differ 
in species (as e.g. Socrates and Coriscus), d we shall 
have to choose (as I have pointed out) e between 

c Lit. " substances." 
* i.e. within the species " man." 
« Above, at 639 a, b, etc. 



644 a > / , / 

Trporepov elirelv ff ttoXXolkls tclvtov Xeyeiv } KaOarrep 

eiprjTdL. (ra oe KaOoXov kolvol' ra yap rrXeioaLv 

VTrdp-^ovra KaOoXov XeyopLev.) a-rroplav 8' e\et Trepl 

TTorepa oel rrpayfiaTeveadat. fj fiev yap ovata to 

so tw etoet cltojjlov, KparcaroVy el rt? Suvcuro, 77€pt toji; 

Ka^' eKaarov Kal drof^cov tw eloet Oewpelv j^wpis, 

(jJ<77T€p 7T€p\ dvOpCOTTOV, OVTW Kal 1 7T€pl OpViOoS, (f<al 

pL7j Trepl orovovv opi'tOosy {^X €L Y®-P € ^ or ) T ® yevos 

TOVTo), dXXd 7T€pl TWV aTOfJLWV' 2 OLOV ff GTpOvOoS fj 

yepavos fj ri tolovtov. fj oe avfififjaeTaL Xeyetv 
35 TToXXaKts Trepl rod avrov irdQovs Sta to Koivfj 
rrXeioaiv VTrdpyeiv, ravrrj 8' iarlv vrrdroTrov Kal 
644 b fJiaKpov to Trepl eKaarov Xeyetv -^wpls. taws p>ev 
ovv opdcus k'xei ra fiev Kara yeviq Kotvfj Xeyeiv, 
baa XeyeTat KaXwg wptapievwv twv dvQpwTrwv y Kal 
ey>ei ~e jilav cf>vatv Kotvr)v Kal etBrj ev avTOLs* firj 
5 ttoXv oteaTWTa, opvis Kal lx@vs, Kal el tl dXXo 
earlv dvcovvfiov piei', tw yevei V ofiola 4 Trepiexet 
ra ev avTw b elBr}' b'aa be jjlt) TotavTa, KaB* 
€KaaTov y oiov Trepl dvOpwTrov Kal et re tolovtov 
erepov euTiv. 

S^eSoy oe tols cr^/xacrt twv pLopiwv Kal rod 
awfiaTos oXov, edv SjjLOLOTrjTa eywaiv , wptaTac ra 
yevrjj oiov to twv dpviQwv yevos rrpos avTo 6 rre- 

1 Kal] fir) Bonitz. 

2 huiic locum correxi, 2 secntus; e^a yap dB-q to yevos 
tovto' aAAa irepi orovovv opviOos tcov arofiajv, oiov ktX. vulg". 

3 avrols vulg. : correxi. 4 ofxoicos vulg. : currexi. 

5 aural vulcr. : correxi. 

6 avro Piatt, fortasse Z 1 : avro Y : aurd Z 2 , vulg. 



describing first of all the general attributes of many 
species, and repeating the same thing many times 
over. (By "general" attributes I intend the 
" common " ones. That which belongs to many we 
call " general.") One may well hesitate whether of 
the two courses to follow. For, in so far as it is the 
specifically indivisible which is the " real thing," it 
would be best, if one could do it, to study separ- 
ately the particular and specifically indivisible sorts, 
in the same way as one studies " Man," to do this 
with " Bird " too, that is. to study not just " Bird " 
in the mass, but — since " Bird " is a group which 
contains species — the indivisible species of it, e.g. 
Ostrich, Crane, and so on. Yet, on the other hand, 
this course is somewhat unreasonable and long- 
winded, because it makes us describe the same attri- 
butes time and again, as they happen to be common 
attributes of many species. So perhaps after all the 
right procedure is this : (a) So far as concerns the 
attributes of those groups which have been correctly 
marked off by popular usage — groups which possess 
one common nature apiece and contain in themselves 
species not far removed from one another, I mean 
Birds and Fishes and any other such group which 
though it may lack a popular name vet contains 
species generically similar — to describe the common 
attributes of each group all together : and (6) with 
regard to those animals which are not covered by 
this, to describe the attributes of each of these by 
itself — e.g. those of Man, and of any other such species 
there may be. 

Now it is practically by resemblance of the shapes 
of their parts, or of their whole body, that the groups 
are marked off from each other : as e.g. the groups 



10 irovQe /ecu to rcov lyBvcov Kal TO. fiaXaKLO. T€ Kal 
ra oorpeia. ra yap fxopia hiatpepovai rovrcov ov 
rfj dvdXoyov 6jJioi6riiri y oiov iv dvBpcoTrco Kal l^Ovi 

7T€7TOv0€V OOTOVV 77pO£ CLKavdaV, dXXd fA&XXoV TOLS 

atofxariKo'is TrdOeaiv, olov fieyeOei fiiKpoTrjrij yiaXa- 
15 k6tt]tl aKXrjporrjTiy Xei6rr]rL rpayyrt]ri Kal tols 


Yicog fxev ovv dirohex^oOai hei rrjv rrepl <f>VG€OJ$ 
fiedohov, Kal riva rpOTrov ylvoir* dv rj Qecopia rrepl 
avrcov ohco Kal paara, en he ~epl hiaipeoetos, riva 
rpOTrov €vhix €rai p-ertovGi Xafifidveiv 17 crista)?, /cat 
20 Slotl to hixorofielv rfj fiev dhvvarov rfj he Kevov, 
eiprjrai. hicopiapievcov he. rovrcov rrepl rcov etpet;fjs 
Xeytofiev, apx^v rrjvhe Troirjodfjievoi, 

V. Tcov ovmtov ooai cpvtrei uvvearaoi, rds (lev 
(Xeyofie^y 1 dyeviqrovs Kal d<f>6dprovs elvai rov 
arravTa alwva, rds he \xereyew yeveoeoos Kal 

25 (j>6opds. GVfXp€^rjK€ 0€ 77601 pL€V €K€Ll'a£ TlfliaS 

ovaas Kal Oeias eXdrrovs rjfxlv virdpy^iv Oecoplas 
(Kal yap i£ tov dv rig UKeifsairo irepl avrcov, Kal 
rrepl tov elhevai TTodovfiev, rravreXcos earlv oXiya ra 
cf>avepd Kara rrjv aiodrjaiv), rrepl he. rcov cf>8aprcov 
<f>VTcov re Kal ^cocov evrropovfxev fiaXXov rrpos rrjv 
80 yvcoaiv hid to crvvrpocfiov 7roXXd yap rrepl eKaarov 
yevog Xdfioi ris dv rcov virapypvrcov f$ovX6p.evos 
hiarroveiv iKavcos. k'^ei 8' eKarepa ydp lv - T( ^v fJ-ev 
yap el Kal Kara fiiKpov e<^arrr6\ieda } ofxcog hid rrjv 

1 (Xeyofiev) Peck. 

Lit., " softies." The group includes, roughly, the 
cephalopod mollusca. 

b Lit., " oysters " (bivalves). 



Birds, Fishes, Cephalopods, a Testacea. & Within each 
of these groups, the parts do not differ so far that they 
correspond only by analogy (as a man's bone and a 
fish's spine) ; that is, they differ not structurally, but 
only in respect of bodily qualities, e.g. by being 
larger or smaller, softer or harder, smoother or 
rougher, and so forth, or, to put it generally, they 
differ " by the more and less." 
We have now shown : 

(1) how to test a method of Natural science ; 

(2) what is the most systematic and easiest way of 
studying Natural science ; 

(3) what is the most useful mode of Division for 
our present purpose ; 

(4) why dichotomy is in one respect impossible and in 
another futile. 

Now that we have made this beginning, and clearly 
distinguished these points, we may proceed. 

V. Of the works of Nature there are, we hold, two Aprotreptic 
kinds : those which are brought into being and perish, |j° am^mah^ 
and those which are free from these processes through- 
out all ages. The latter are of the highest worth and 
are divine, but our opportunities for the study of 
them are somewhat scanty, since there is but little 
evidence available to our senses to enable us to con- 
sider them and all the things that we long to know 
about. We have better means of information , howe ver , 
concerning the things that perish, that is to say, plants 
and animals, because we live among them ; and any- 
one who will but take enough trouble can learn 
much concerning every one of their kinds. Yet 
each of the two groups has its attractiveness. For 
although our grasp of the eternal things is but 
slight, nevertheless the joy which it brings is, by 



TLfJLLOTTjTQ. TOV yVLOp'l^eiV rjhlOV f) TO. Ttap TJfJLlV 

aTTavra, djarrep Kal rtov epajfievcov to rvydv Kal 

35 fXLKpOV flOpiOV KClTl&eiV TjhlOV €OTLV Tj TToXXd €T€pOL 

645 a Kai fieydXa oV aKpiBelas IheZv ret he hid to fiaXXov 
Kal TrXeLto yvwpi^eiv avrcov XapL^dvei rrjv rrjs 67Tt- 
crrrjfJLrjs VTrepoxtfi', €tl he htd to TrXrjaiairepa rjficov 
elvat Kal rrjs (jyvaeevs olKeiorepa avriKaraXXdr- 
reral rt rrpos rr)v rrepl rd 9eta <j>iXoao<f)Lav , errel 
5 he Trepl eKetvatv htrjXOof.Ler Xeyovres to tfiaivofievov 
rjfjuVy Xolttov Trepl rrjs ^toiKrjs ebveretos elrrelv, fX7]hev 
TrapaXiTTOvras els hvvap.iv firjre drtfiorepov firjre 
TLpLLcorepov. Kal yap ev rots f^r) Kex^piGj-ievois 
avrcov rrpos rr]v atcrOrjaLV Kara rrjv decoptav Sfitos 1 
7] hrjfjLLOVpyrjcracra <f>vcri$ dfirj^dvovs rjhovds irapeyei 

10 rols hwafievois rds alrias yvcopl^etv Kal tf>vo~ei 
tbiXocrotboLS . «al yap av etrj rrapdXoyov Kal arorrov y 
el rds piev elKovas o.vrcov Oecopovvres x a ' L P°l JLev ^ TL 
rrjv hrjfjLiovpyqoaoav 7eyyf)v avvOecopovfiev, otov rrjv 
ypa<f>iK7)v r) rrjv TrXaariKi-jv, avrcov Se rcov tf>voei 
uvveurcorcov piTj jjiaXXov dyarrcpfiev rrjv Oewplav, 

15 hwdfievoi ye rds alrias KaOopav. hid hel fj.rj 
hvax e P a ^ V€LV TraihiKcbs rrjv rrepl rcov dripLorepcov 
t^cptov eTTLGKeifjiv ev rraoi yap rots </>vglkols eveari 

1 opcos Bekker : opoitos codd. 

a This passage, 645 a 6-15, is quoted by R. Boyle (Of the 
Usefulnesse of Xaturall Philosophy, 1663) both in Gaza's 
Latin version and in an English translation, and he intro- 
duces it thus : " And, methinks, Aristotle discourses very 
Philosophically in that place, where passing from the con- 
sideration of the sublimist productions of Nature, to justifie 
his diligence in recording the more homely Circumstances of 
the History of Animals, he thus discourses." He also quotes 


reason of their excellence and worth, greater than 
that of knowing all things that are here below ; just 
as the joy of a fleeting and partial glimpse of those 
whom we love is greater than that of an accurate 
view of other things, no matter how numerous or how 
great they are. But inasmuch as it is possible for us 
to obtain more and better information about things 
here on the earth, our knowledge of them has the 
advantage over the other ; and moreover, because 
they are nearer to us and more akin to our Nature, 
they are able to make up some of their leeway as 
against the philosophy which contemplates the things 
that are divine. Of " things divine " we have al- 
ready treated and have set down our views concerning 
them ; so it now remains to speak of animals and 
their Nature. a So far as in us lies, we will not leave 
out any one of them, be it never so mean ; for though 
there are animals which have no attractiveness for 
the senses, yet for the eye of science, for the student 
who is naturally of a philosophic spirit and can dis- 
cern the causes of things. Nature which fashioned 
them provides joys which cannot be measured. If we 
study mere likenesses of these things and take pleasure 
in so doing, because then we are contemplating the 
painter s or the carver's Art which fashioned them, and 
yet fail to delight much more in studying the works 
of Nature themselves, though we have the ability to 
discern the actual causes — that would be a strange 
absurdity indeed. Wherefore we must not betake 
ourselves to the consideration of the meaner animals 
with a bad grace, as though we were children ; since 
in all natural things there is somewhat of the mar- 

the following passage, a 15-23, describing it as 4 1 that Judicious 
reasoning of Aristotle." 

i>2 99 


n OavfJLaGTOV' Kal KaOdvrep ' Hpa/cAetTOS" Aeyerat 
20 Trpos rovs ^ivovs eiTrelv rovs fiovXopievovs evrvx^v 
avroo, 61 irreLor) 7Tpoai6vreg eloov avrov Oepopuevov 
irpos ra> Irrvcp earrjcrav (ihceAeve yap avrovs etcrteVat 
Oappovvras' etvai yap Kal ivravda Beovs), ovrco /cat 
rrpos rrjv ^rfrrjaiv irepl ihcdorov tcov ^cocov rrpoaUvai 
Set fjirj ovacorrovfjievov, cos iv diraaiv ovros nvos 
(fyvoLKod Kal KaXov. 

To yap firj rvxovrcos aXX eW/ca rtvos iv tois Trjs 
25 <f)VG€CL>s epyous iarl /cat fidXiara' ov S' eVe/ca 
<jvv€gtt}K€v rj yeyove tAou?, ttjv rod KaXov j(wpav 
etXrjtfrev. el Se tls rrjv 7repl tcov dXXcov ^cpcov 
Oecopiav drifiov elvai vevd/ut/ce, rov avrov rporrov 
o'UaOat XPV 77€ P*' avTO v' ovk eart yap dvev 

TToXXrjs Svax^petas ISetv cbv gvv€gtt}K€ to tcov 
80 dvOpcoircov yevos, olov at/xa, adpKes, o'crra, cfyXefies 
Kal rd roiavra fiopia. ofiolcos re Set vojiL^eiv rov 
Trepl ovtlvogovv tcov ptopicov rj tcov GKevcov Sta- 
Xeyofievov firj 7rept Trjs vXrjs 770tetcr#at ttjv \xvr\psc\v, 
fjirjSe ravrrjs x®-P lv > dXXd rrjs oXrjs fjiop<f)rj$, olov /cat 
77ept ot/ctas 1 , dXXd firj ttXlvOcov /cat 7TTjXov /cat tjvXcov 

35 Kal TOV 7T€pl <f>VG€COS 7T€pl TTjS GVv94o€CO<$ Kal TTjS 

oXrjs ovalas, dXXd firj irepl tovtcov a firj ai>/xj8atVet 
Xoop^ofievd ttot€ Trjs ovalas avrcov. 

° Or, with reference to another use of ozWa, " which gives 
them their being." Independent approaches to the position 
that components are non-significant in isolation had been 
made, e.g. by Anaxagoras, as a physical philosopher (see 
my article in C.Q. xxv. 27 ff., 112 ff.), who held that " the 
things (i.e. the constituent elements) in this world are not 
separate one from another" (frag. 8, Diels, Fragmente 5 , 



vellous. There is a story which tells how some 
visitors once wished to meet Heracleitus, and when 
they entered and saw him in the kitchen, warming 
himself at the stove, they hesitated ; but Heracleitus 
said, " Come in ; don't be afraid ; there are gods 
even here." In like manner, we ought not to hesi- 
tate nor to be abashed, but boldly to enter upon our 
researches concerning animals of every sort and kind, 
knowing that in not one of them is Nature or Beauty 

I add " Beauty/' beeause in the works of Nature 
purpose and not accident is predominant ; and the 
purpose or end for the sake of which those works have 
been constructed or formed has its place among what 
is beautiful. If, however, there is anyone who holds 
that the study of the animals is an unworthy pursuit, 
he ought to go further and hold the same opinion 
about the study of himself, for it is not possible 
without considerable disgust to look upon the blood, 
flesh, bones, blood-vessels, and suchlike parts of 
which the human body is constructed. In the same 
way, when the discussion turns upon any one of the 
parts or structures, we must not suppose that the 
lecturer is speaking of the material of them in itself 
and for its own sake ; he is speaking of the whole 
conformation. Just as in discussing a house, it is the 
whole figure and form of the house which concerns us, 
not merely the bricks and mortar and timber ; so in 
Natural science, it is the composite thing, the thing 
as a whole, which primarily concerns us, not the 
materials of it, which are not found apart from the 
thing itself whose materials they are. a 

59 b 8) ; also from the logical point of view, as seen in 
Plato, Theaetetus, 201 e ff. 



645 b 'AvayKcuov Se irptorov rd crvpifiefirjKOTa hieXelv 
7T€pl €k<iotov yevos , ooa kclQ 7 avrd rrduiv vTrdpxei 
tols Repots, pera 8e ravra rds* alrtag avrwv Treipa- 
<j6<jl SieXeiv. eipr)rai pev ovv /cat rrporepov on 
vroXXd Koiva ttoXXols vrrdpx^i rwv ^tptvv, rd p,ev 
a-nXchg (olov TroSeg, Tirepd, XeTTihes, /cat TrdOrj Srf 
rov avrov rpoTTOV tovtois), rd 8' dvdXoyov (Xeyaj 8' 
dvdXoyov, on tols pev VTrdpxei TrXevpwv, tols Se 
rrXevpwv pev ov, o he roig k'xovoi irXevpova, eKei- 
vois erepov dvrl rovrov /cat tols pev aipa, rots 8e 

10 to dvdXoyov rrjv avr-qv e\ov hvvapiv rjvTrep rots 
evatp.ois to alpa) • to Se Xeyeiv x^pls irepi eKaorwv 
tojv /ca#' eKaara, /cat epTrpouBev eliropev on 
TToXXaKis GvpLprjaeTai Tavrd Xeyeiv, erreiSdv Xe- 
ywpev rrepl irdvrcov tojv vnapxovTajv vrrapxei Se 
rroXXols Tavrd. ravra piev ovv ravrj] SiwploOw. 

15 'Evret 8e to p.ev dpyavov rcdv eveKa rov, tojv Be 
rod awparos poplow eKaorov eveKa rov, to 8' ov 
eveKa Trpd^Ls tls, (f>avepov on /cat to ovvoXov oxo/za 
avvearr]Ke 7rpd£eiLs nvos eveKa rroXvpLepovs } ov 
yap rj rrplais rov rrpiovos X®-P lv y^Y 0V ^ v > dAA' 6 
irplojv rrjg irpioews' XPV GL $ 7^-P Tt? V ^P 101 ^ eorlv. 
ware Kal to acopd ttojs rrjs faxVS eveKev, /cat rd 

20 piopia rwv epycvv rrpos a ne^VKev eKaarov. 

AeKreov dpa TTpwrov rds Trpd^eis rds re KOivds" 

1 7ro\vfj,€povs P : TrX-qpovs vulg. : fortasse 7io\v{x6p(f>oVy cf. 
646 b io. 

2 TraiTcov post Koivas vulg. ; delevi. 

° Almost always used in the singular by Aristotle. 

h By " blood " Aristotle means red blood only. " Blooded " 
and *' bloodless " animals do not quite coincide with verte- 
brates and invertebrates ; for there are some invertebrates 
which have red blood, e.g. molluscs (Planorbis), insect 


First of all, our business must be to describe the Final 
attributes found in each group ; I mean those of the 
"essential" attributes which belong to all the Metllod * 
animals, and after that to endeavour to describe the 
causes of them. It will be remembered that I have 
said already that there are many attributes which 
are common to many animals, either identically the 
same (e.g. organs like feet, feathers, and scales, and 
affections similarly), or else common by analogy 
only (i.e. some animals have a lung, others have no 
lung but something else to correspond instead of 
it ; again, some animals have blood, while others have 
its counterpart, b which in them has the same value 
as blood in the former). And I have pointed out 
above that to treat separately of all the particular 
species would mean continual repetition of the 
same things, if we are going to deal with all their 
attributes, as the same attributes are common to 
many animals. Such, then, are my views on this 

ow, as each of the parts of the body, like every 
other instrument, is for the sake of some purpose, 
viz. some action, it is evident that the body as a 
whole must exist for the sake of some complex 
action. Just as the saw is there for the sake of 
sawing and not sawing for the sake of the saw, 
because sawing is the using of the instrument, so in 
some way the body exists for the sake of the soul, 
and the parts of the body for the sake of those 
functions to which they are naturally adapted. 

So first of all we must describe the actions (a) 

larvae (Chironomns), worms (Arenicola). In other in- 
vertebrates the blood may be blue (Crustacea) or green 
(Sabellid worms), or there may be no respiratory pigment 
at all (most insects). 



645 b ^ ^ > 

Kal ras Kara yevos Kal ras Kar* etSos 1 . Xeyco oe 
kolvcls fJLcv at iraoiv vrrdpxovcn roig Repots, Kara 
yevos Se oacov nap* aAA^Aa tol$ Statpopds opcofiev 

25 /ca#' V7T€pox^]v ouaa?, olov opviOa Xeyco Kara yevos, 
dvOpojTTOv he Kar ethos, Kal ttclv o Kara rov 
kolQoAov Xoyov ixrjheyiiav e\ei Stacpopdv. ra fiev 
yap €)(ovaL to kolvov /car' avaXoylav , ra he Kara 
yevos > ra Se Kar elSos. 

"Ocrat fiev ovv rrpd^ets aAAajy eveKa y S^Aoy ort 
Kal cov al rrpd^eis rov avrov rporrov hieuraoiv 

30 ovTrep al 77 pd^eis. oyioicos he Kav el rives rrporepai 
Kal reXos erepcov irpd^ecov rvyxdvovatv ovaac } rov 
avrov e^et rponov Kal rcov \xoplcov eKaarov cov at 
rrpd^ecs at rotayrat- /cat rplrov i a rivcov 1 ovrcov 
dvayKatov vrrapxeiv. (Xeyco he rrddf] /cat rrpd^eis 
yeveatVy av^rjaiv, d^etW, eypr\yopaiv ', vttvov, tto- 

35 p€tav> Kal ottog aAAa roiavra rols Repots VTrdpxer 
fjiopta he Aeyaj plva y 6(f>QaXfi6v Kal to awoAov 

646 a 7rp6cra>7T0v t cov eKaarov KaXelrai fieXos. SfJLolcos 

he Kal Trepl rcov aAAajy.) 

Kat rrepl fiev rod rpoirov rrjs fieOohov rocavB* 
7]{ilv elprjaOw ra? S' atrta? TreLpaOcofiev elrrelv rrepl 
re rcov kolvcov Kal rcov lSllov, dp^dfievot, Kaddirep 
hicopiaajiev, repcorov airo rcov rrpcorcov. 

1 a rtvwv Peck, cf. 677 a 18: wv vulg. : a tovtojv Ogle. 

a See above, note on 644 a 17. 
* Examples will occur during the course of the treatise. 



which are common, and those which belong (6) to a 
group, or (c) to a species. By " common " I mean 
those that are present in all animals ; by " those 
which belong to a group " I mean those of animals 
whose differences we see to be differences " of 
excess " a in relation to one another : an example of 
this is the group Birds. Man is an example of a 
species ; so is every class which admits no differ- 
entiation of its general definition. These three sorts 
of common attributes are, respectively, (1) analogous, 
(2) generic, (3) specific. 

Now it is evident that when one action is for the 
sake of another action, then the instruments which 
perform the two actions differ exactly as the two 
actions differ : and if one action is " prior " to another 
and is the " end " of that other action, then the part 
of the body to which it belongs will be " prior " to 
the part to which the other action belongs. There 
is also a third possibility, viz. that the action and its 
organ are there simply because the presence of others 
necessarily involves them. 6 (By affections and actions 
I mean Generation, Growth, Copulation, Waking, 
Sleep, Locomotion, and the other similar ones that 
are found in animals. Examples of parts are : Nose, 
Eye, Face ; each of these is named a " limb " or 
" member." And the same holds for the rest too.) 

Let this suffice concerning the method of our 
inquiry, and let us now endeavour to describe -the 
causes of all these things, particular as well as 
common ; and, according to the principles laid down, 
we will begin with the first ones first. 



*EiK tlvwv fiev ovv fioptojv Kal ttogwv aw- 


10 7T€pl avTwv o€oi]\toTai (ja(f)loTepov 8t' as 8* out tot? 


Xojploavras kolO* avra. twv iv rats LGTOplais €tprj- 


TpLwv 8' ovgwv twv avvOeGewv TTpcurrjv fxiv av 
tls Oelr] n)v Ik twv KaXovfiivwv vtto tlvojv gtol- 
yeiwv } oiov yrjs, aipos, voaros, rrvpos. eVt oe 
is j34Arcov cgqjs €K rwv Svvd(jL€Cov XiyeLv, Kal TOVTWV 
ovk i£ OLTraawv, dAA' wGTrep iv eTepoLs elprjTai Kal 
npoTepov vypov yap /cat £r]pdv Kal Oeppiov Kal 
ifjvxpov vXrj twv gvvQItwv GCofiaTajv ZgtIv, at 8' 
d'AAat 8ta</>opat TavTais &KoXov9ovGLV y olov fidpos 


20 xuTTjs Kal Xetorrjs Kal TaAAa tol TotauTa TrdOrj twv 
GWjiaTwv. hevTepa he GVGTaais €K twv irpwTwv r) 


ogtov Kal GapKos Kal twv d'AAa>v twv tolovtwv. 

° For the threefold series cf. Be gen. an. 714- a 9 fT. This 
first " composition " seems to be intended to cover -non- 
organic compounds. 

b " Dynamis " here is clearly the pre- Aristotelian technical 
term. See Introduction, p. 3U. c See JJe gen. et corr. chh. 2, 8. 

d In some contexts, " fluid " and *' solid " seem more 


I have already described with considerable detail J^jP£* e * nd 
in my Researches upon A?iimals what and how many the treatise, 
are the parts of which the various animals are 
composed. We must now leave on one side what 
was said there, as our present task is to consider 
what are the causes through which each animal is as 
I there described it. 

Three sorts of composition can be distinguished. 
(1) First of all a we may put composition out of the 
Elements (as some call them), viz. Earth, Air, Water, 
Fire ; or perhaps it is better to say dynameis b instead 
of Elements— some of the dynameis, that is, not all, 
as I have stated previously elsewhere." It is just 
these four, the fluid substance, the solid/ the hot, and 
the cold, which are" the matter of composite bodies ; 
and the other differences and qualities — such as 
heaviness lightness, firmness looseness, roughness 
smoothness, etc.— which composite bodies present 
are subsequent upon these. (2) The second sort of 
composition is the composition of the "uniform"* 
substances found in animals (such as bone, flesh, 
etc.). These also are composed out of the primary 

appropriate ; in others, " moist " and 11 dry " (the traditional 
renderings). Aristotle defines them at De gen. and corr. 
329 b 30. See also below, 64-9 b 9. I have normally trans- 
lated them " fluid " and lk solid " throughout. 

* u Uniform,' 1 " non-uniform " ; see Introduction, p. 28. 



646 a f 

t piTTj Kal TeXevraia kglt dpiOjidv rj ra>v av- 

ojjLOioiiepcov olov TTpoocbirov Kal x €L P°$ Ka ^ T & v 


25 'E7T€t 8' ivavTicos inl Trjs yeveoecos e^et Kal Trjs 
ovalas — ra yap vcrrepa rfj yeveoei irporepa Tr)v 
(f>voiv eori s Kal rrpcoTOV to rf} yeveoei reXevralov 
(ov yap OLKia ttXlvOcov eveKcv ion Kal Xt8o)v t dXXa 
ravra Trjs ot/aas" dfioicos be tovt e^et Kal nepl rrjv 
aXXiqv vXrjv ov [jlovov be (j)avepov on tovtov k'yei tov 

so Tponov €K Trjs eTraywyrjs, dXXd Kal Kara, tov Xoyov 
TTav ydp to yivofievov €K twos Kal els ti rroieiTai 
Tr)v yeveoiv, Kal an' dpx^js ^ 77 ' ^PXV V > c ^ 770 rr ) s 
7rpcoTrjs Kivovorjs Kal exovorjs rjbrj two, <f>voiv iwL 
Tiva fjL0p<f)7]v rj tolovtov dXXo TeXos* avdptoiros ydp 
avdpwirov Kal (f>VTOv yevva <f>VTOV €k Trjs rrepl 

35 (EKaOTOV V7TOK€LjJi€Vrj$ vXr]$) TO) fJL€V OVV XpOVO) 

646 b rrpoTepav tt)V vXrjv dvayKalov etvai Kal Trjv yeveoiv, 
tw Xoycp be TTjv ovolav Kal rrjv eKaoTOV fJLop(f>rjv. 
brjXov 8' dv Xeyrj tls tov Xoyov Trjs yeveoew 6 [xev 
yap Trjs oiKobopirjueaiS Xoyos e^et tov ttjs oiKias, 
6 be Trjs otKLas ovk e^et tov Trjs olKobopnqoecos . 

5 OfJLOLWS be TOVTO OVfJL^e^TjK€ Kal €7tI TWV d'XXcOV . 

cuCTTe Tr)v /xev toov oToixeicov vXrjv dvayKalov elvai 
twv opLoiofxepcov ev€K€i" voTepa ydp €K€LVaJV TavTa 

a Or, " efficient." 
h Or, " in thought,'" " in conception." 
e Almost represented here by " definition.'* 



substances. (3) The third and last is the composition 
of the " non-uniform " parts of the body, such as 
face, hand, and the like. 

Now the order of things in the process of formation 
is the reverse of their real and essential order ; I 
mean that the later a thing comes in the formative 
process the earlier it comes in the order of Nature, 
and that which comes at the end of the process is at 
the beginning in the order of Nature. Just so bricks 
and stone come chron ologically before the house, 
altho ugh the house is tne purpose which they sub - 
s erve, and not vice versa. And tne same applies to 
materials ot every kind. Thus the truth of my state- 
ment can be shown by induction ; but it can also 
be demonstrated logically, as follows. Everything 
which is in process of formation is in passage from 
one thing towards another thing, i.e. from one Cause 
towards another Cause ; in other wordsT it proceeds 
from a primary motive a Cause which to begin with 
possesses a definite nature, towards a Form or an- 
other such End. For example, a man begets a man 
and a plant begets a plant. These new indi- 
viduals are made out of the substrate matter appro- 
priate in each case. Thus, matter and the process 
of formation must come first in time, but logically 6 
the real essence and the Form of the thing comes 
first. This is clear if we state the logos of such a 
process. For example, the logos of the process of 
building includes the logos of a house, but that of a 
house does not include that of the process of building. 
And this holds good in all such cases. Hence we 
see that the matter, viz. the Elements, must exist 
for the sake of the uniform substances, because 
these come later in the process of formation than 



rfj yevecrec, rovrojv be ra avofiocofjuepr). ravra yap 
77877 to reXos €^et /cat to irepas, eirl rod rpirov 
Xaftovra rrjv ovoraoiv dpidpiov, KaOdirep errl ttoXXcov 
10 ovfJifiaLvet, reXeiovoOat rag yevecreis. 

'E£ d{JL(f)OT€pa>V jl€V OVV TO. £dja GVV€OTTlK€ TO)V 

puepwv eveKev iartv eKetvwv yap epya Kal rrpd^eig 
eloiv, otov o^OaXpLod /cat pbVKrijpog Kal rod npoa- 
cottov TTavros Kal haKrvXov Kal %eipds Kal TTavros 

lb rov fipaxLovos. 7ToAvf.l6p(f)a)V §€ TQJV irpd^ewv Kal 
rwv Kivrjcrewv VTrapxovawv rolg t,<l)Ois oXois re Kal 
rois ybopioLs rdls roiovrois, dvayKalov i£ wv avy- 
Keivrai rag hvvdpieig avojJLolas e\etv irpds i±ev yap 
rcva fjLaXaKorrjs -vpr^OLjios rrpos he rtva GKXrjp6rr)s , 
Kal ra jxev rdaiv ^X eiv Tt * ^ Kapufjiv. 

20 Td jxev ovv 6fJLOLOfj.epr] Kara fiepos StetA^e Tas" 
hvva^eig ras roiavras (to fiev yap avrwv eari 
puaXaKov ro he a/cA^poV, Kal to fiev vypdv ro he 
£j]p6v y Kal ro fjbev 1 yXtaxpov ro he Kpavpov), ra 
h' dvopLOto/jieprj Kara rroXXds Kal avyKeLfievas 
dAA^Aat?- erepa yap irpos ro irieaai rfj X €L P^ XPV~ 

25 at/xo? hvvafjLLS Kal TTpog ro Xafieiv. hioirep e£ 
oarwv Kal vevpwv Kal aapKos Kal rwv d'AAojv rwv 
rotovrwv Gvveori]Kaai ra opyaviKa rwv {loplwv, 
dAA' ovk eKeiva £k rovrwv, 

r ils" fJLev ovv eveKa rtvos hid ravrrjv rrjv alrlav 
e'xei irepl rovrwv rdv elprj^ievov rpouov, eirel he 
t > r\reir at Kal ttws dvayKalov e^etr ovrw, <f>avep6v on 

80 TTpovTrrjpx^ ovrw irpds aXXiqXa exovra i£ dvdyK7]s 

1 to fiev PZ : om. vulg, 



the Elements ; just so the non-uniform parts eome 
later than the uniform. The non-uniform parts, 
indeed, whose manner of composition is that of the 
third sort, have reached the goal and End of the 
whole process ; and we often find that processes of 
formation reach their completion at this point. 

Now animals are composed out of both of these two 
sorts of parts, uniform and non-uniform ; the former, 
however, are for the sake of the latter, as it is to the 
latter that actions and operations belong (e.g. eve, 
nose, the faee as a whole, finger, hand, the arm as a 
whole). And inasmuch as the actions and movements 
both of an animal as a whole and of its parts are mani- 
fold, the substanees out of which these are composed 
must of necessity possess divers dynameis. Softness is 
is useful for some purposes, hardness for others ; 
some parts must be able to stretch, some to bend. 

In the uniform parts, then, such dynameis are 
found apportioned out separately : one of the parts, 
for instance, will be soft, another hard, while one is 
fluid, another solid ; one viscous, another brittle. 
In the non-uniform parts, on the other hand, these 
dyna?neis are found in combination, not singly. For 
example, the hand needs one dynamis for the aetion 
of compressing and another for that of grasping. 
Hence it is that the instrumental parts of the body 
are composed of bones, sinews, flesh, and the rest of 
them, and not the other way round. 

The Cause which I have just stated as controlling 
the relation between them is, of course, a Final 
Cause ; but when we go on to inquire in what sense 
it is necessary that they should be related as they are, 
it beeomes clear that they must of necessity have 
been thus related to each other from the beginning. 



646b ^ „ 

ra fiey yap avofioiojiepfj it< rcov ofioiofxepcov ev- 

Se^crai avveardvai, Kal €K rrXeiovtov Kal ivos, otov 

evta rcov GrrXdyxycov iroXvyLop^a yap rots ^X 7 !" 

fiaoiv, i£ ofioiofjiepovs ovra utopLaros cos elireiv 

airXws. ra 8' 6jj,OLO[ieprj €K tovtcov dSvvarov to 

55 yap 6fioiOjj,€p€s 7T6XX* av €Lrj dvofiOLOfieprj. 
647 a Aid fiev ovv ravras rds alrlas Tct [lev drrXa Kal 
ofJLoiojjLepfj, ra Se ovvdera Kal dvopLOLOfieprj rcov 
fioplcov iv rots £ojois" ivriv. 

"Ovtcov §€ row (lev opyavLKcbv fiepcov rcov 8' 
alaOrjrrjpLcov iv rots ^toots, tcov piev opyavtKcbv 
5 cKaorov dvojjLOLOjJiepes ionv, cocnrep elrrov irporepov, 
r) 8' atoOrjois iyylverai iraoiv iv rots opLOioyLepioiv 
oia to rcov alodr^cretov oiroiavovv ivos rivos etvai 
yivovsj Kal to alo6rjrr)pLov iKaurov $€Ktlk6v elvai 
rcov atoOrjrcov. 77ao%et 8e to Swdfiei ov vno rod 
ivepyelq. ovros, coot eon to avro rep yivei } Kal 

10 (ety 1 iKetvo ev y Kal rovro ev, Kal Sid rovro X € ^P a 
fiev rj rrpoucoTTOV rj rcov tolovtcov ri \xopLcov ovSels 
iy^ipet Xeyetv rcov <j>voioX6ycov to pciv elvai yrjv, 
to 8' vocop, to Se rrvp' rcov 8' alodrjrrjpLCOv eKaarov 

1 <«> Ogle. 

° The translation *' sense-organ " must not be taken to 
imply that the part through M'hich the sense functions is an 


It is possible for the non-uniform parts to be con- 
structed out of the uniform substances, either out of 
many of them, or out of one only. (Examples of the 
latter are furnished by certain of the viscera, which, 
although they are of manifold shapes and forms, 
yet for all practical purposes may be said to consist 
of one only of the uniform substances.) But it is 
impossible for the uniform substances to be con- 
structed out of the non-uniform parts : for then 
we should have an uniform substance consisting of 
several non-uniform parts, which is absurd. 

These, then, are the Causes owing to which some of 
the parts of animals are simple and uniform ; while 
others are composite and non-uniform. 

Now the parts can also be divided up into (a) 
instrumental parts and (b) sense-organs. And we 
may say that each of the instrumental parts of the 
body, as I have stated earlier, is always non-uniform, 
while sensation in all cases takes place in parts that 
are uniform. The reasons why this is so are the 
following : The function of each of the senses is 
concerned with a single kind of sensible objects ; and 
the sense-organ in each case must be such as can 
apprehend those objects. Now when one thing 
affects another, the thing which is affected must be 
potentially what the other is actually ; so both are the 
same in kind, and therefore if the affecting thing is 
single, the affected one is single too. Hence we 
find that while with regard to the parts of the 
body such as hand, or face, none of the physiologers 
attempts to say that one of them is earth, and 
another water, and another fire ; yet they do conjoin 

" organ " in the stricter meaning of the word. " Organs " 
are normally " non-uniform,' 1 sense-organs are " uniform." 



Trpos" €Kclotov eTn^evyvvovoL tcov oTot^etaw, to /xet^ 
defpa cf)doKovT€s eivat, to 8e rrvp. 

0va7]s Se T7js" alo6rjO€OJS iv tols arrXols fiepeaw 
15 euAoyaj? judAtcrra au/x^atWt r^y dc/^y eV 6[ioLO{i€pel 
fjiev rjKiora 8' d7rAai rdiv al(j6r]Trjp ta>v iyylveoBar 
/zdAtcrra yap atn-17 So/cet 7rAetoVajv etrat yevaw, /cat 


Bepjiov ipvxpov, fypov vypov Kal el tl dXXo TOLOVTOV 


dvdXoyov, GcofiaTCoSecjTaTov eart tcov aluOrjTrjpicov. 
irrel 8' dhvvaTov elvai i^coov avev aioQ^cjzcos , /cat 
8td tovto dv eirj dvayKolov e^eiv tols Ccools eVta 
jiopia opLOLOfieprj' r) {lev yap aio9i]ULS iv tovtols, 
at 8c Trpd^eis Std tcov dvofiOLOfiepcov virdp^ovoiv 

25 Trjg 8' aloOrjTiKrjs Swdfiewg Kal Trjs Kivovarjs 

TO £,CpOV Kal T7]S 9p€TTTLK7js €V TaVTW flOpLCp TOV 

OiojiaTOs ovor)s y Kaddirep iv irepois elprjTai irpo- 
Tepov, dvaytcaiov to €X ov irpcoTov jiopiov Tag 
TOtavTag dpyds, fj fiiv eort Sektlkov irdvTCov tcov 
aiuOrjTcov, tcov dirXcov elvai jioplcov, f) Se klvtjtlkov 

30 Kal TTpaKTtKOVy TCOV dvOfJLOLO[JL€pCOV . hlOTTep iv fJL€V 

Tolg dvaljiOLs Repots to dvdXoyov, iv Se rot? ivaljiois 
r) Kaphla toiovtov euTLV Statpetrat [lev yap els 
opLOLOfieprj Ka9a7T€p tcov dXXcov arrXdyxvcov eKaorov, 
Std Se T7)V tov cr^/xaros' pLoptfirjv dvoyLoioyiepis 
ioTiv. TavTTj 8' 7]KoXov0rjKe Kal tcov dXXcov tcov 


See Be somno, 455 b 34 ff. 


eaeh of the sewse-organs with one of the elementary 
substanees, and they assert that this sense-organ is 
air, this one fire. 

Sensation thus takes place in the simple parts of 
the body. The organ in which touch takes place is, 
however, as we should expect, the least simple of all 
the sense-organs, though of course like the others it 
is uniform. This is evidently because the sense of 
touch deals with more kinds of sense-objects than 
one : and these objects may have several sorts of 
oppositions in them, e.g. hot and cold, solid and fluid, 
and the like. So the sense-organ which deals with 
these — viz. the flesh, or its counterpart — is the most 
corporeal of all the sense-organs. Another reason 
we might adduce why animals must of necessity 
possess some uniform parts at any rate, is that there 
cannot be such a thing as an animal with no power 
of sensation, and the seat of sensation is the uniform 
parts. (The non-uniform parts supply the means for 
the various activities, not for sensation.) 

Further, since the faculties of sensation and of 
motion and of nutrition are situated in one and the 
same part of the body, as I stated in an earlier work, a 
that part, which is the primary seat of these principles, 
must of necessity be included not only among the 
simple parts but also among the non-uniform parts — 
the former in virtue of receiving all that is perceived 
through the senses, the latter because it has to do 
with motion and action. In blooded animals this 
part is the heart, in bloodless animals the counterpart 
of the heart, for the heart, like every one of the other 
viscera, can be divided up into uniform pieces ; but 
on the other hand it is non-uniform owing to its 
shape and formation. Every one of the other so- 



647 a 

35 KaXovfievajv arrXdyx^wv eKaarov €K rrjs avrrjs 
647 b yap vXrjs avvtoraow alfxarLKr] yap r) (f>vois udvTWV 
avTwv Sia to ttjv dioiv ^X €LV ^opot? (f>Xef3iK0is 
Kal SiaArjifjecnv. KaOdrrep ovv piovTos vSaros IXvs, 
TaXXa airXdyxya ttjs hid twv (frXefiwv pvaewg rod 
atpLaros olov Trpo^vixard iariv* rj 8e KapSia, Sia 
5 to twv cfyXefiwv dpx?) etrai Kal ^x elv *- v a ^ T V T V V 
Svvafiiv rrjv SrjfJLLovpyovcav to alfia rrpwTrjv, ev- 
Xoyov iij ota? dpx^Tat 1 Tpocf>rjs eV ToiavTrjs ovv- 
eOTavai Kal avTrjv. 

Atdrt [lev ovv ai/xartKa ttjv fxop(f)7]v ra oirXdyxya 
€gtlv etprjTai, Kal StoVi Tjj p,ev opLoiofiepfj Tjj 8' 

io II. Twv 8' ofJLOiofiepwv [loplwv iv tols Scoots iarl 
ra [xev [xaXaKa Kal vypd s tcl 8e cr/cA^pa Kal aTeped, 
vypa [lev rf oXws rj ecus dv fj iv rfj (f>VG€i, olov 
af/xa, Ix&p, TripLeXf), GTeap, piveXos, yovf], X°^V> 
ydXa iv tols e^oucrt, odpt;, Kal ra tovtols dvdXoyov 

15 ov yap diravTa ra £a)a tovtwv twv jxoplwv re- 
Tevx^Vy dAA' evta twv dvdXoyov tovtwv tlclv. ra 
Se £rjpa Kal crrepea twv ojJLOiojxepwv ioTiv, olov 
OGTOvVy aKavOa, vevpov, (f>Xiip. Kal yap twv 6/jLolo- 
fjiepwv r) Statpecri? e^et $ia<f>opdv €oti yap ws iviwv 
to fiipos ofjLwvvfjLov tw SXw , otov cfrXefids </)Xeift, €oti 

•20 8' ws ovx SfJLwvvfJLov, dXXa npoacoTrov irpoawnov 

1 ota? corr. in loco phirium litterarum Y : oi a?Z (a? Z 2 in 
rasura). apxerat (vel apxrj eVrt) Peck, cf. 666 a 7, b 1, etc. : 
Several vulg. 



called viscera follows suit. They are all composed 
of the same material, as they all have a sanguineous 
character, and this is because they are situated 
upon the channels of the blood-vessels and on the 
points of ramification. All these viscera (excluding 
the heart) may be compared to the mud which 
a running stream deposits ; they are as it were 
deposits left by the current of blood in the blood- 
vessels. As for the heart itself, since it is the starting- 
point of the blood-vessels and contains the substance 
(dynamis) by which the blood is first fashioned, 
it is only to be expected that it will itself be com- 
posed out of that form of nutriment which it 

We have now stated why the viscera are san- 
guineous in formation, and why in one aspect they are 
uniform and in another non-uniform. 

II. Of the uniform parts in animals, some are The uniform 
soft and fluid, some hard and firm. Some are parts * 
permanently fluid, some are fluid only so long as they 
are in the living organism — e.g. blood, serum, lard, 
suet, marrow, semen, bile, milk (in the lactiferous 
species), flesh. (As these parts are of course not to 
be found in all animals, add to this list their counter- 
parts.) Other of the uniform parts are solid and 
firm : examples are bone, fish-spine, sinew, blood- 
vessel. This division of the uniform parts admits a 
further distinction : There are some of them of which 
a portion has, in one sense, the same name as the 
whole (e.g. a portion of a blood-vessel has the name 
blood-vessel), and in another sense has not the 
same name. (In no sense is this the case with a 
non-uniform part ; for instance, a portion of a face 
cannot be called face at all.) 



647 b x f , x 

^TjpOlS 77oAAot T pOTTOL TTjS CUT I a? elo'lV. TO, fieV yap 

u>$ vXrj rcbv jiep&v rtov dvojioioyLepcov euriv (eK 
rovrcov yap ovveoT7]Kev eKaorov rcov opyavtKchv 
jiepojVy i£ ogtcdv Kal vevpojv Kal uapKtov Kal oXXojv 
25 tolovtojv vvjj.fiaXXoyLevcDV ra jikv els rrjv ovoiav ra 
S' els tt]v ipyaalav), ra. he TpO(j>rj tovtols tlov 
vypojv iurl (jTavra yap e£ vypov Xap.fidvei n)v 
av^rjotv), ra he TrepiTTOjjiaTa ovfifiefirjKev ehai 


Kal rrjv rr)S vypds rots k^ovGL kvgtlv. 

Kvtwv he tovtojv at hta<f)opal TTpog dXXrjXa tov 

30 fieA-LOVOS eV€K€V €LGLV, OLOV TO)V T€ dXXa)V Kal 

alyLaros 7Tp6s at/.ta* to yukv ydp Xeirrorepov to he 
TrayvTepov /cat to fxev KaOapwrepov eon to ok 
OoXepcorepoVy ere he to ipvy^poTepov to he Bep- 
liorepoVy ev Te tols piopiois tov evos £,ojov (to ydp 
35 iv tols avco fiepeot rrpos ra Kara) fiopia hia<f>epei 
Tavrais Tat? hta^opals) /cat irepaj irpds erepov, 

648 a /cat oXws Ta fikv evaifia tojv L.ojojv early ra 8' avrl 

tov aifJLaros k'xei erepov tl fiopLov tolovtov. 

"Eo*Tt 8* taxvos jikv TTOirjTLKLurepov to Traxvrepov 
alfia /cat OeppiOTepov > alcOrjTtKwTepov hk Kal voepoj- 
repov to XeTTTorepov Kal ifjvxporepov . tyjv aijTrjv S' 
5 k'xei hia<f)opdv Kal to avdXoyov inrdpxov 1 7Tp6s to 

1 to . . . vTrdpxov P : rwv . . . v7TapxoiTcov vulg. 

° Or, " reason. " 

b See Introduction, pp. 32 ff. 

c See Introduction, pp. 28 fF. 

d With this passage compare Hippocrates, Ucpl Siairgs, 
i. 35. See also below, 650 b 24 ff., and Introduction, pp. 


Now first of all there are many sorts of Cause a to 
which the existence of these uniform parts, both the 
fluid and the solid ones, is to be ascribed. Some of 
them act as the material for the non-uniform parts 
(e.g. each of the instrumental parts is composed of 
these uniform parts — bones, sinews, fleshes, and the 
like, which contribute either to its essence, or else 
towards the discharge of its proper function). An- 
other group of the uniform parts — fluid ones — act as 
nutriment for the ones just mentioned, since every- 
thing that grows gets the material for its growth 
from what is fluid ; and yet a third group are residues 6 
produced from the second group : examples, the 
excrement deposited from the solid nutriment and 
(in those animals which have a bladder) from the fluid 

Further, variations are found among different 
specimens of these uniform parts, and this is to sub- 
serve a good purpose. Blood is an excellent illustra- 
tion. Blood can be thin or thick, clear or muddy, 
cold or warm ; and it can be different in different 
parts of the same animal : instances are known of 
animals in which the blood in the upper parts differs 
from that in the lower parts in respect of the char- 
acteristics just enumerated. And of course the 
blood of one animal differs from that of another. 
And there is the general division between the 
animals that have blood and those which instead of it 
have a part c which is similar to it though not actually 

The thicker and warmer the blood is, the more it 
makes for strength ; if it tends to be thin and cold, 
it is conducive to sensation and intelligence.^ The 
same difference holds good with the counterpart of 



8a v 

at/xa- S16 kou jxeXirrai kou d'AAa roiavra £a)a <ppo- 

vificorepa rrjv tfivcnv iarlv IvaLjicov ttoXXcov, Kal rcov 

ivaifJLCov rd ipvxpov exovra Kal Xerrrov atfia <f>povi- 

jxcorepa rcov ivavrlcov icrrlv. apicrra Be rd Ocpfiov 

10 e^ovra koll XeTrrov Kal KaOapov a/xa yap irpos r 

dvhpeLav ra roiavra Kal Trpog cfrpovrjoiv e^et KaXcos. 

Sio /cat ra dvco pcopca irpos rd Kara* ravrrjv e^ei 

rrjv Sia^opdV, Kal TTpos to drjXv av to dppev, Kal 

TOL Se^LOL 7Tp6$ TO, OLptGT€pOL TOV CTCOfJiarog. 

'OfioLcos Kal Trepl rcov aXXcov Kal rcov roiovrcuv 
15 pLopitov Kal rcov avojJLOiojJLepcbv VTToXrjTTrdoV €\€IV 
rijv htatfiopdv, rd fxev rrpos ra epya Kal rrjv ova Lav 
eKaarq) rcov t^cocov, rd he irpd$ to fieXriov o} ^etpov, 
olov exovrcov 6(f)9aXfj.ovg dpicfiorepcov rd \iiv iari 
a KXrjpocpO aXpca rd 8' vypochOaXpia, Kal rd jxev ovk 
e^€t j3Xe<f)apa rd §' e^ei, 7Tp6g to rrjv oifttv aKpi- 
f$€crr€pav eh'at. 
20 "On 8' dvayKalov ex €lv V a ^ a V TO rovrco rrjv 
avrrjv ex ov (frvcriv, Kal ris luriv r) rod alfiaros 
(j>vuiSy irpcorov hceXofievois irepl Otpjiov Kal ifivxpov, 
ovrco Kal TTepl rovrov Oecoprjreov rd$ air las. ttoXXcov 
yap r) cfivcrts dvdyerat rrpos ravras rds dpxdg, Kal 
25 7ToAAot SiafxcpLaprjrovat TTOia Oepjxd Kal 7701a ifsvxpd 
rtov c^cpcov rj rcov fioptcov. eviot yap rd evvBpa rcov 
ire^cov 0€pfx6r€pd cf>acnv etvat, Xeyovreg cos iiraviaol 
rrjv ifjvxporrjra rov roirov rj rrjs tftvcrecos avrcov 

a This sentiment, which at first sight appears to go against 
the Aristotelian teleology, is supported by actual instances, 
e.g. the horns of the backward-grazing oxen (659 a 19) and 
of the deer (663 a 1 1) and the talons of certain birds (694 a 20). 


blood in other creatures : and thus we can explain 
why bees and other similar creatures are of a more 
intelligent nature than many animals that have 
blood in them ; and among the latter class, why 
some (viz. those whose blood is cold and thin) are 
more intelligent than others. Best of all are those 
animals whose blood is hot and also thin and clear ; 
they stand well both for courage and for intelligence. 
Consequently, too, the upper parts of the body have 
this pre-eminence over the lower parts ; the male over 
the female ; and the right side of the body over the 

What applies to the blood applies as well to the 
other uniform parts and also to the non-uniform 
parts ; similar variations occur. And it must be 
supposed that these variations either have some re- 
ference to the activities of the creatures and to their 
essential nature, or else bring them some advantage 
or disadvantage. For example, the eyes of some 
creatures are hard in substance, of others, fluid ; 
some have eyelids, others have not. In both cases 
the difference is for the sake of greater accuracy of 

Before we can go on to consider the reasons why all 
animals must of necessity have blood in them or some- 
thing which possesses the same nature, and also what 
the nature of blood itself is, we must first come to 
some deeision about hot and cold. The nature of many 
things is to be referred back to these two principles, 
and there is much dispute about which animals and 
which parts of animals are hot and which are cold. 
Some assert that water-animals are hotter than land- 
animals, and they allege that the creatures' natural 
heat makes up for the coldness of their habitat. 



648 a / ^ ( , v 

OepfJLOTTjs, Kal ra dvaifia tw^ ivaLfiwv Kai ra urjXea 

twv dppevwv, oiov HapfJieviorjs rag yvvaiKag twv 
30 avSpcDr Oepfjuorepas elvai <f)r)oi Kal erepot rives wg 
Sia tt)^ OepfJLor^ra Kal rroXvai fiova aig yivo\iivwv 
twv yvvaiK€Lcm> y 'EfJLirehoKXrjs he rovvavriov en 8' 
at/xa /cat x°^V v 0<i H-^ v ^ € PH-ov oTrorepovovv elvai 
<f>aaiv avrwVy ol he ipvxpdv. S' e^€t rooavT7}v 

TO OepjJLOV Kal TO IpVXpOV GLfl(f)l(jljriT7)(7LV, tl XPV 

35 7T€jOt rcov aAAojy viroXafSe iv ; Tavra ydp rjfjuv iv 
apyeorara twv trepl rrjv aicr8r]oiv. 
"Eoixre he hid to TroXXaxw XeyeoOai to Oepfio- 
648 b Tepov ravra ovpfialveiv eKaorog ydp hoKei tc 
Xiyeiv rdvavrla Xiywv, hid hei pirj XavOdveiv n wg 
Set twv <f>vcr€t, ovvearwrwv ra [xev Oepfid Xiyeiv Ta 
8e ipvxpd Kal Ta fxev £r)pa ra §' vypd y irrel on y 
atrta ravra ax^hdv Kal Oavdrov Kal ^wrjg eoiKev 
5 eivai <f>avep6v, en S' vttvov Kal iyprjydpaewg Kai 
aKjJLfjs Kal yi)pwg Kal vooov Kal vyieiag y dXX ov 
TpaxvTTjTes Kal Xei6r7]reg ovhe ^apvrrjreg Kal kov- 


Kal tovt evXoywg ovpifiefiiqKev' KaOdnep yap iv 
irepoig elpyyrai rrporepoVy dpx&l t&v <f>vaiKwv 
10 GTOLx^cwv avrai eloi s Oeppidv Kal ifjvxpdv Kal 
^rjpdv Kal vypov. 

Yldrepov ovv drrXwg Xeyerai to Oeppidv t) rrXeo- 
vax&g; hei hr] Xafieiv tl epyov rov OepfioripoVy rj 
a See above, 646 a 15, and note. 



Further, it is asserted that bloodless animals are 
hotter than those that have blood ; and that females 
are hotter than males. Parmenides and others, for 
instance, assert that women are hotter than men on 
the ground of the menstrual flow, whieh they say is 
due to their heat and the abundance of their blood. 
Empedocles, however, maintains the opposite 
opinion. Again, some say that blood is hot and bile 
cold, others that bile is hot and blood eold. And if 
there is so much dispute about the hot and the cold, 
which after all are the most distinct of the things 
which afFeet our senses, what line are we to take 
about the rest of them ? 

Now it looks as if the difficulty is due to the term Tho primary 
" hotter " being used in more senses than one, as there ("^hot^ ' 
seems to be something in what each of these writers and "cold." 
says, though their statements are contradictory. 
Henee we must permit no ambiguity in our application 
of the descriptions " hot " and 4 * eold," " solid " and 
" fluid " to the substances that are found produced by 
nature. It is surely sufficiently established that these 
four principles (and not to any appreciable extent 
roughness, smoothness, heaviness, lightness, or any 
sueh things) are practically the causes controlling life 
and death, not to mention sleep and waking, prime 
and age, disease and health. And this, after all, is 
but reasonable, because (as I have said previously in 
another work) these four — hot, cold, solid, fluid — are 
the principles of the physical Elements. a 

Let us consider, then, whether the term " hot " 
has one sense or several. To decide this point, we 
must find out what is the particular effeet which a 
body has in virtue of being hotter than another, or, 
if there are several such effects, how many there are. 




648 b 

Trdcra, el TrXetaj. eva fikv Srj rpoirov Xeyerat fiaXXov 
Oepjxov v<f> ov jjl&XXov OepfiaLverai to drrTOfievov, 
15 aXXcos ok to fx&XAov aiuOrjoLv Ifirroiovv iv ra> 
dtyydveiv, Kal tovt \ lav fiera Xvtttjs. eon 5° ore 
$OK€L tovt alvai ipevoos' iviore yap r) e£is atria 
rod aXyeiv aioQavofilvois . €tl to TrjKTLKcoTepov rod 


fj to fikv ttXeov to 8' eXarrov to avTo, to ttXIov tov 
20 iXaTTovos BepjJLOTepov. Ttpos hk tovtols hvotv TO 
fir) ra^ecus" ipvxdfievov aXXa fipahews OepfiOTepov, 


jipaSecos OepfiOTepov etvai tt)v <f>voLV <f>afiiv, cos to 
fikv Ivavrlov otl iroppto, to 8' ofioiov otl iyyvg. 
Xeyerat fikv ovv el fir) rrXeovaxcos, dXXd ToaavTaxtos 


ahvvaTOv vrrdpx^LV tlq aura) TrdvTas' Oepfxalvei fikv 
yap uaXXov to l^cov vhcop tt)s <}>Xoy6s, KaUi hk /cat 

TT)K€C TO KaVUTOV Kal TTJKTOV i) <f>X6£ , TO S' vScop 

ovSev. €TL OepfioTepov fxev to X^iov vBcop r) Tivp 
dXlyov, ifjvx eraL $k Kat OoLttov Kal fidXXov to Oepfiov 

30 vBcop pLLKpov TTvpos' ov yap ylv€Tai ipvxpov rrvp, 
vScop 8k ytVcrcu tt&v. ert OepfxoTepov fikv Kara tt)v 
d<j>r)v to t^iov v8top J tpvx €T0LL 8k Odrrov Kal rrr\yvvTai 
tov iXalov. €Ti to atfia Kara, fikv Tr)v d(f>r)v Oepfio- 
repov vSaTos Kal IXaiov, 7Tr)yvvTai 8k 6&ttov. €tl 
XlOol Kal Gihrjpos Kal tol rotaura flep/xatWrat fikv 

35 fipaovTepov v8aTos, KaUi ok OepfiavOevra fiaXXov. 
Trpos ok tovtols rcov Xeyof-ievtov Oepfitov tol fikv 

° Alluding, perhaps, to the expansion due to heat. 



A is said to be " hotter " than B (1) if that which 
comes into contact with it is heated more by it than 
by B. (2) If it produces a more violent sensation 
when touched, and especially if the sensation is 
accompanied by pain. (The latter is not always a 
true indication, since sometimes the pain is due to the 
condition of the percipient.) (3) If it is a better 
melting or burning agent. (4) If it is of the same 
composition as B, but greater in bnlk. a it is said to be 
"hotter" than B, and in addition (5) if it cools 
more slowly than B, or warms up more quickly : in 
both these cases we call the thing " hotter " in its 
nature — as we call one thing " contrary " to another 
when it is far removed from it, and " like " it when 
it is near it. But although the senses in which 
one thing is said to be " hotter " than another 
are certainly as many as this, if not more, yet 
no one thing can be " hotter " in all of these 
ways at once. For instance, boiling water can im- 
part heat more effectively than flame ; but flame 
is able to cause burning and melting, whereas 
water is not. Again, boiling water is hotter than 
a small fire, but the hot water will cool off more 
quickly and more thoroughly than the small fire, 
since fire does not become cold, but all water 
does. Again, boiling water is hotter to the touch 
than oil, yet it cools and solidifies more quickly. And 
again, blood is warmer to the touch than either water 
or oil, yet it congeals more quickly. Again, stone 
and iron and such substances get hot more slowly 
than water, but once they are hot they burn other 
things more than water can. In addition to all this 
there is another distinction to be made among the 
things that are called " hot " : in some of them the 



649 a dXXorplav e^ei rr)v OepfJLorrjTa ra S' oiKelav, Siu- 
cf>ep€t Se to Oepfiov elvai ovtlos r) €K€LVCos rrXeiOTOv, 
iyyvs yap tov Kara avfxPeprjKos tlvai Bzpyiov dXXd 
fir) kolO* avro Odrepov avrcov Loorrtp dv ei tis Xiyoi, 
6 el ovfJifiefirjKos elrj tco Trvpirrovri elvai (jlovglkoj, 
tov fjLovaiKov elvai BeppLorepov r) tov fieO* vyielas 
OepfJiov. irrel S* earl to fiev kol6* avro BeppLOV to 
Se Kara GvpifiefiriKos , ifjvx €TaL fiev fipaovrepov to 
Ka6* avro, Bepfxalvet Se pidXXov rroXXaKis rrjv at- 
oBrjoiv to Kara ovfJLfiefirjKos' koi rrdXiv Kalei fiev 

10 fiaXXov to Ka6* avro Bepfiov, olov r) cf>X6^ rod 
vSaros rov ^eovrog, Beppaivei Se Kara rrjv d(j>r)v to 
^€OV pL&XXov, to Kara GvjjLfieprjKos Beppov. ware 
(f>avep6v on to Kplvat ovoiv rrorepov Bepporepov ovx 
drrXovv tool fiev ydp ToSe earat BzppoTepoVy cool Se 

15 Oarepov. kvia Se rcov tolovtlov ouS' eariv olttXlos 
elrrelv on Bepjiov r] pr) Beppov* o pev ydp rrore 
rvyxdvet ov to vrroKeipevov ov Beppov, ovvova^o- 
pevov Se OepfioVy olov ei tis BeiTo ovopia voari rj 
crLorjpa) Bepptp' tovtov ydp tov rpoirov to af/xa 

OepflOV €GTLV. KOI 770166 ok <f)CLV€p6v €V TOLS TOLOV- 

20 Tot? oti to ifjvxpdv <f)vois rig dXX* ov areprjols iortv, 
iv oools to V7TOK€LfJL€VOV Kara rrdBos BzppLov ionv. 
rdxa Se koll r) rod rrvpos (frvcris, €i eri^e, toiolvtt) 
tls ioTtv icrws ydp to vrroKelpevov euTiv rj Karrvos 
r) dvBpa£ } tov to pev del Beppov (dvaBvpLtaais ydp 6 
Karrvos), o 8' dv9pa£ drroofieoBels i/jvxpds. eXaiov 
Se Kal rrevKr) yivoiT dv ifivxpd. exec Se BeppoTryra 

° That is, " blood " is really " hot a%" and the " x " is no 
more hot of its own nature than the " water " in " hot water." 
Cf. 649 b 21 ff., and Torstrik, Rh. Mus. xii. 161 ff. 

h Perhaps a reference to the resin which is in fir wood or is 
obtained from it. 


heat is their own ; in others it has been derived from 
without. And there is a very great difference be- 
tween these two ways of being hot, because one of 
them comes near to being hot " by accident " and 
not hot " of itself" ; as is obvious, supposing anyone 
were to assert, if a fever-patient were " by accident " 
a man of culture, that the man of culture is hotter 
than a man whose heat is due to his perfect health. 
Thus some things are hot " of themselves " and 
some hot " by accident," and though the former cool 
more slowly, the latter are in many cases hotter in 
their effect upon the senses. Again, the former have 
a greater power of burning : e.g. a flame burns you 
more than boiling water, yet the boiling water, 
which is hot only " by accident," causes a stronger 
sensation of heat if you touch it. From this it is 
plain that it is no simple matter to decide which of 
two things is the hotter. The first will be hotter in 
one way, and the second in another. In some cases 
of this sort it is actually impossible to say simply that 
a thing is hot or is not hot. I mean cases in which 
the substratum in its permanent nature is not hot, 
but when coupled (with heat) is hot ; as if we were 
to give a special name to hot water or hot iron : that 
is the mode in which blood is hot. a These cases, in 
which the substratum is hot merely through some 
external influence, make it clear that cold is not just a 
privation but a real thing in itself. Perhaps even fire 
may be an instance of this kind. It may be that its 
substratum is smoke or charcoal : and, though smoke 
is always hot because it is an exhalation, charcoal 
when it goes out is cold. In the same way oil 
and flrwood b become cold. Further, practically all 



649a f f ^ 

25 /cat tol TTVpwOivra Travra cr^eSdv, otov Kovla /cat 
re^pa, /cat tcl VTToarrjfiaTa twv ^wwv, /cat twv 
TrepiTTW\xaTWV r) X°^V> T( ? > ^f-^^vpeduOat /cat 
iyKaraXeXeL(j)6aL ri iv avrolg Qep^iov. aXAov he 


fidXXeiv els evepy etav irvpos* 

30 Ao/cet he. to Qepiiov /cat 7rrjyvvvat /cat Ti]Ketv. ova 
fjcev ovv vhaTo$ LLovov y raura mjyvvGL to ifivxpov, 
oo~a he yrjs, to rrvp- /cat twv Oepfxwv TrrjyvvTai vtto 
ifjvxpov tolxv fiev Sua yrjs fidXXov /cat olXvtlos, 
Xvtws 8' ocra vhaTOS. aAAcx ire pi {lev tovtwv ev 
eTepois hiwpiOTdi Ga^>eGTepov y irola tol TrrjKTd, /cat 
TTTfyvvTai hid Tivas atrta?. 

35 To 8c tl QepLiov /cat ttoIov OepfioTepov e7Teihrj 
649 b XeyeTai irXeovax&s , ov tov avTov Tpoirov virdp^ei 
tt&glv, dXXd TrpoahiopiGTeov ort kcl6* olvto fiev ToSe, 
/cara avLLfiefirjKos he iroXXaKis QaTepov, 2, ert he 
Svvdfiei fiev ro8t, ro8t he /car' evepyeiav, /cat Tovhe 

{lev TOV TpOTTOV ToSt, TO) fJL&XAoV TTjV dcfjTjV Qep- 

5 fiaiveiv, tool he. tw <f>X6ya rroielv /cat nvpovv. 
Xeyofxevov he tov Oeppcov rroXXaxws, a/coAou^cret 
hrjXov oti /cat to ifjvxpov /cara, tov clvtov Aoyov. 

Kat irepi [lev Oepjiov /cat ipvxpov /cat Trjs 
V7repox?l$ CLVTtbv hiwpiaOw tov Tporrov tovtov. 
III. ^xofievov he /cat Trepl £r]pov /cat vypov SteA- 
io 9e1v aKoXovdws rot? elpr^ievois . XeyeTai he raura 

1 Bepiia Peek : flepjuov vulg. 
2 ttoWo-kis Odrepov] num raAAo depjiorepov? 

° See Meteor. 382 b 31 ff., 3S8 b 10 ff. 

6 Probably the text should be altered to read : " B hotter 
by accident " 

s See note on 646 a 16, and Introd. p. 32. 


things that have passed through a process of com- 
bustion have heat in them, such as cinder, ash, the 
excrement of animals, and bile (an instance of a 
residue). These have passed through fire and some 
heat is left behind in them. Firwood and fatty 
substances are hot in another way : they can quickly 
change into the actuality of fire. 

We must recognize that " the hot " can cause both 
congealing and melting. Things that consist of 
water only are solidified by the cold, those that con- 
sist of earth, by fire. Again, hot things are solidified 
by cold : those that consist chiefly of earth solidify 
quickly, and the product cannot be dissolved again ; 
those that consist chiefly of water can be dissolved 
after solidification. I have dealt more particularly 
with these matters in another work, a where I have 
stated what things can be solidified, and the causes 
that are responsible for it. 

So, in view of the fact that there are numerous 
senses in which a thing is said to be " hot " or " hotter," 
the same meaning will not apply to all instances, but 
we must specify further, and say that A is hotter 
" of itself," B perhaps " by accident " h ; and again 
that C is hotter potentially, D actually ; and we 
must also say in what way the thing's heat manifests 
itself : e.g. E causes a greater sensation of heat when 
touched ; F causes flame and sets things on fire. 
And of course, if " the hot " is used in all these 
senses, there will be an equal variety of senses 
attaching to " the cold." 

This Mill suffice for our examination of the terms 
" hot " and " cold/' " hotter " and " colder." 

III. It follows on naturally after this to discuss (&) "solid" 
"the solid" and "the fluid " c on similar lines. and " fluId '" 



649 b 

TrXeovaytbs , olov ra puev hvvdfxec ra S' evepy eia. 
KpvoraXXos yap Kal ttov to neirrjyos vypov Xeyerat 
£v}pa x fiev evepyela Kal Kara. ovfjifiefirjKos, ovra 
hvvdfxet Kal KaO* avrd vypd, yrj he Kal r£(f>pa Kal 

15 Ta rotaura fiixOevra vyptp evepy eta fiev vypd Kal 
Kara ovfLpefirjKos, KaQ* avra he Kal hwdfjuet ^y]pd' 
hiaKpiOevra he. ravra ra fiev vharos dvaTrXrjGTLKa 
Kal evepyeia Kal hvvdfiei vypd, ra he yijs arravra 
£r]pdj Kal to Kvplojs Kal drrXws £v)pdv tovtov 
fidXiara Xeyerai tov rponov. ofioccos he Kal ddrepa 

20 ra vypd Kara rov avrov Xoyov eyei* to Kvpltos Kal 
drrAws, Kal eirl Oepficov Kal i/jvxpwv. tovtcov he 
hiwpiGfievojv cfyavepov on to alfia d)8l fiev eun 
depfiov [olov rl 2 rjv avrto to aljian elvai;\ KaBdirep 
yap 2 el dvofiarl nvi* arffialvocfiev to t^eov vhtop, 
ovrco Xeyerai' to o° viroKeifievov Kal 6 irore ov 

25 alfid euriv, ov Oepfiov Kal Ka6* avrd eon fiev cbs 
Oepfiov eGTiv y eon §' d>s ou* ev fiev yap ra> 
Xoyto vrrdp^ei avrov r) Oepfiorrfs, worrep iv tqj 
rod XevKov dvdpcorrov to XevKov r) he Kara rrdOos, 
to atfia ov KaO* avrd Oepfiov. 1 * 

'Ofioitos he Kal rrepl tjrfpov Kal vypov, hid Kal 

1 ^7]pa Peck : £-qpov viilg. 
2 olov ti Bekker. haec, signo interrog. adscr., seclusi. 
3 yap Z : om. vulg. 


5 11. 22-29 interpunctionem correxi. 

° i.e. they assume the shape of the receptacle into which 
they are put. 



These terms are used in several senses. E.g. 
" solid " and " fluid " may mean either potentially 
solid and fluid or actually solid and fluid. Ice 
and other congealed fluids are said to be solid 
actually and by accident, though in themselves and 
potentially they are fluid. On the other hand, earth 
and ash and the like, when they have been mixed 
with a fluid, are fluid actually and by accident, but 
potentially and in themselves they are solid. When 
these mixtures have been resolved again into their 
components, we have on the one hand the watery 
constituents, which are anaplestic, a and fluid actually 
as well as potentially, and on the other hand the 
earthy components which are all solid : and these 
are the cases where the term " solid " is applicable 
most properly and absolutely. In the same way, 
only those things which are actually as well as poten- 
tially fluid, or hot, or cold, are such in the proper 
and absolute sense of the terms. Bearing this dis- 
tinction in mind, we see it is plain that in one way 
blood is hot [e.g. what is the essential definition of 
blood ?], for the term " blood " is used just as the 
term for " boiling water " would be, if we had a 
special name to denote that ; but in another way, 
i.e. in respect of its permanent substratum, blood is 
not hot. This means that in one respect blood is 
essentially hot, and in another respect is not. Heat 
will be included in the logos of blood, just as fair- 
ness is included in the logos of a fair man, and in 
this way blood is essentially hot ; but in so far as 
it is hot owing to external influence, blood is not 
essentially hot. 

A similar argument would hold with regard to the 
solid and the fluid. And that is why some of these 



€V T7} <j)VG€l TWV TOIOVTWV TCL fJL£V U€p(ia KCLl Vypa, 

30 xcopi^ofJieva Se 7T7^yyf rat kcu ipvxpd <f>atv€rai, oiov 
to atfia, tcl 8e Oepfia Kal ^d^os 1 k\ovTa KaOdirep rj 
Xo^r), x co P L £°l jLeva ^ * K <f>v0€a)s Twv Ixovtwv 
TOVvavTiov ira<jx €l ' ^X £Tat Y^P vypaweTCU' to 
fxev yap atjLta ^paiVrat ^dAAov, vypalveTai §' 17 
£av6y} x°^l' T ° ^ fiaAAov /<at ^ttov p.€T€X €l ' v T ^ v 

35 dvTlK€lfl€VLOV WS VffdpXOV 1 §€t TlOeVCLL TOVTOl$ . 

650 a riajs* juev ow Oepfjiov Kal ttws vypoVy koli ttws 

TWV ivaVTLCDV Tj <f)VGl$ TOV at/XaTOS* K€KOlVWV7]K€V, 

eiprjTai ax^oov. 

'E77€t 8' dvdyKTj irdv to av^avojievov \ap.f$dv€iv 
Tpo^rjVy rj §€ Tpo(j)rj nauiv vypov Kal ^rjpov, Kal 
5 tomtom; 77 7T€ifji$ ylveTai Kal rj fieTafSoXr) Std ttJs" tol» 
Oepfiov SvvdfjLecos, Kal Ta £(2>a rrdvTa Kal ra <f)vrd, 
Kav el p.7] Si' d'AA^v air lav, dAAa Sid TavTrjv dvay- 
Kaiov Zx €lv < *PXV V QzpP-ov cf>VGLKrjv. [Kal TavTrjv 
wanep] at {S') 2 ipyaoiai ttjs Tpo^fjs irXeiovwv eici 
[JLOpltOV 7} pi€V ydp TTpCOTTj <j>avepd rots* £06019 
10 XetTovpyla Sid tov crTOfiaTOS ovaa Kal twv ev 
tovtw [loplwv, oawv rj Tpo<j>y] Seirai Siaipeaew?. 
dAA' ami] (Jiev ovSepuas airia neifiews, dAA' ev- 
rretjjLas fiaXXov rj yap els puKpa Sialpeais tt)s 
Tpocf)rjg paw Ttoiei tw Oepfiw ttjv ipyaaiav rj he Trjs 
dvw Kal Trjs KaTW KoiAias* rjhrj /xerd OepfJLOTTjTOs 

1 vnapxov Peck : VTHxpxovra vulg. 

9 Kal ravr-qv coa-nep seclusi, (§') supplevi : Kal ravr-qv 
(TrXeloot fxoplois €vv7rdpxovGav) Camus. 

a See above, note on 644 a 17. 
b See Introduction, p. 34. 

c Lit. " the dynamis of the hot substance," 1 perhaps here 
something more than a mere periphrasis for " the hot sub- 


substances while in the living organism are hot and 
fluid, but when separated from it congeal and are 
observed to be cold, as blood does ; others, like 
yellow bile, are hot and of a thick consistency while 
in the organism, but when separated from it undergo 
a change in the opposite direction and become cool 
and fluid. Blood becomes more solid, yellow bile 
becomes fluid. And we must assume that " more 
and less " a participation in opposite characteristics 
is a property of these substances. 

We have now pretty well explained in what way 
blood is hot, in what way it is fluid, and in what 
way it participates in opposite characteristics. 

Everything that grows must of necessity take food. 
This food is always supplied by fluid and solid matter, 
and the concoction b and transformation of these is 
effected by the agency of heat. c Hence, apart from 
other reasons, this would be a sufficient one for 
holding that of necessity all animals and plants 
must have in them a natural source of heat ; though 
there are several parts which exert action upon the 
food. In the case of those animals whose food needs 
to be broken up, the first duty clearly belongs to 
the mouth and the parts in the mouth. But this 
operation does nothing whatever towards causing 
concoction : it merely enables the concoction to 
turn out successfully ; because when the food has 
been broken up into small pieces the action of the 
heat upon it is rendered easier. The natural heat 
comes into play in the upper and in the lower gut, 

stance," as emphasizing its proper and specific natural 
character, which makes it a particularly good agent for 
effecting concoction. See Introduction, pp. 30-32. 



650 a 

15 <j>vGiKrjs TTOieTrai rrjv rriifjiv. woirtp Se /cat to 
arofjca ttjs aKarepydcrTOV Tpo<f)r)s 7ropog e'crrt, /cat 
to aw€X€s ai)Tw popiov o KaXovGiv olao^dyov, 
oaa twv £>wwv e^ei tovto to pidpiov, iwg elg 
ttjv KoiXlav, ovtw /cat dXXovs Set TTopovg 1 elvai, 01 
&v array Xrjifjerai to uwpa ttjv Tpocf>r]v, cuGirep 

20 €K <f)aTVf]Si €K Trj$ KOlXldS Kdl Tjjs TWV il'TEpWV 

<f>va€W$. ret p,ev yap <j)VTa Xapfidvei rr)v Tpocf>r]v 
KaT€Lpyaafievrjv e'/c Trjs yijg rat? pl^aig (Sto /cat 
TT€piTTto\xa ov ytVerat Toig (j)VTolg- Tjj yap yfj /cat 
Tjj iv avTfj OepjxoTYjTi xpfj Tai <%>cr7T€p KoiXia), to, Se 
£<pa 7rdvTa pev o^eoov, ra Se rropzVTiKa ^avepws, 

25 otov yrjv iv avTols e'^et to Trjs /cotAtas" kvtos, it; 
rjSy worrep e/cetva rats' pl^ais, raura Set tlvI ttjv 
Tpo<j>r)v Aa/x/3avetv, ecus* to Trjs e'^ofteV^s" rriifjews 
Xdfij] re'Aos*. r) pev yap tov OTOftaros ipyaula rrapa- 
SIScoctl Tjj /cotAta, rrapd Se TavTrjs €T€pov dvayKalov 
Xapfidveiv, oirep ovpfiefir]K€V' at yap cf)Xifle$ /cara- 

30 T€ivovTai Sid tov peoevTeplov rrapdrrav, KaTwOev 
dp^dpievai p-i-XP 1 T V S xoiXiag. Set Se Taura QewpeTv 
e/c re twv avaTopwv /cat Trjs <j>vaiKrjs loToplag. 

'E-n-et Se 7rdor)s Tpocf)fjs e'crrt rt Bektlkov /cat twv 
yivo\xivwv 7T€piTTWfAaTWv, at Se (frXefies otov dyyetov 
alpaTog etcrt, cf>av€pov otl to alpa r) TeXevraia 

35 Tpocf>rj Tot? £>wois rot? ivaipioig iorl, tois S' dvalp.ois 

1 dXXovs Set nopovs Peck : aAAay dpxas Bet ttXzlovs vulg. 

a Cf. Shakespeare, CorioJanus i. i. 133-152. 

b The membrane to which the intestines are attached. 

c Dissectioyis (or Anatomy) is a treatise which has not 


which effect the concoction of the food by its aid. 
And, just as the mouth (and in some animals the 
so-called oesophagus too which is continuous with 
it) is the passage for the as yet untreated food, and 
conveys it to the stomach ; so there must be other 
passages through which as from a manger the body 
as a whole may receive its food from the stomach and 
from the system of the intestines.* Plants get their 
food from the earth by their roots ; and since it 
is already treated and prepared no residue is pro- 
duced by plants — they use the earth and the heat 
in it instead of a stomach, whereas practically all 
animals, and unmistakably those that move about 
from place to place, have a stomach, or bag, — as it 
were an earth inside them — and in order to get the 
food out of this, so that finally after the successive 
stages of concoction it may reach its completion, they 
must have some instrument corresponding to the 
roots of a plant. The mouth, then, having done its 
duty by the food, passes it on to the stomach, and 
there must of necessity be another part to receive it 
in its turn from the stomach. This duty is under- 
taken by the blood-vessels, which begin at the bottom 
of the mesentery, 6 and extend throughout the length 
of it right up to the stomach. These matters should 
be studied in the Dissections c and my treatise on 
Natural History. d 

We see then that there is a receptacle for the food 
at each of its stages, and also for the residues that 
are produced ; and as the blood-vessels are a sort of 
container for the blood, it is plain that the blood (or 
its counterpart) is the final form of that food in living 

d The Natural History, otherwise History of Animals or 
Researches vpon Animals. See 495 b 19 ff., 514 b 10 ff. 



to dvdXoyov. Kal hid tovto firj Xa^dvovaL re 
650 b rpo<f>rjV vttoX€L7T€l tovto Kal Xafi^dvovotv au^dVerat, 
Kal xprjcrTf}s fxev ovor}$ vyieivov, (fxxvXrjs he <f>avXov. 
oti [xev ovv to aljJLa rpo(j)rjs eveKev vnapxet rots' 
evalpiois, <f>avepdv €K tovtcov Kal tcov toiovtcov. Kal 
yap hid tovto §iyyavo\ievov aiadrjoiv ov Troiet 
5 (tuoTTep oi5S* d'AAo tcov irepiTTcojiaTCOv ovhev } ovh* rj 
Tpo(f)Tj) KaQdrrep odp^' 1 avTTj yap diyyavo\ievr\ iroiei 
alaOrjoiv. ov yap avvexes euri to at/xa TavTrj ovhe 
avfjL7Te<f)VK6$ } dAA' otov ev dyyeico Tvyydvei Keifxevov 
ev Te Tjj Kaphia Kal rat? <f>Xeifj[v. ov Be rpoTrov 
Xanfidvei e£ avTov to. fxopia ttjv av^rjoiv, eVt he 

10 nepl Tpotfirjs oXtoSj ev Tolg irepl yevevetos Kal ev 
eTepots oiKeiorepov eoTi hieXQeiv. vvv §' IttI 
ToaovTOV elprfoOco (tooovtov yap xp 1 ] <JL { JL0V ) > otl T ° 
at/xa Tpo(f>fjs eveKa Kal Tpo<j>rjs tcov \ioplcov euTiv. 
IV. Tds* he KaXovfxevas tvas to fxev k'xei af/xa 

Vo to S' ovk e'^ei, otov to tcov eXdcpcov Kal irpoKcov. 
hiorrep ov TrrjyvVTai to tolovtov af/xa* rod yap 
alfxaTog to jxev vharcohes /xaAAdv 2 cart, hid Kal ov 
TrrjyvVTai, to he yecoheg Trr\yvvTai crvve^aTfJLi^ovTos 
tov vypov- at §' tve? yfjs eloiv. 

Zu/x/fatWt §' evid ye Kal yXacpvpcorepav eyeiv 

•:o rrjv hidvoiav tcov tolovtcov, ov hid ttjv ipvxpoTTjra 
tov at/xaTos-j dXXd hid ttjv XerrTOTrjTa fiaXXov Kal 

1 11. 4 f., interpunctionem correxit Cornford. 
2 fxa^ov Z : fidXXov ipvxpov vulg. 

° In the Second Book. Also in De gen. et corr. 

6 With the sentiments of the following passage and its 
terminology (" more intelligent,' 1 " soul," " blend," etc.) 
compare the very interesting passage in Hippocrates, ITept 
BtaiTTjSi i. 35. Cf. 64-S a 3. 


creatures. This explains why the blood diminishes 
in quantity when no food is taken and increases 
when it is ; and why, when the food is good, the 
blood is healthy, when bad, poor. These and 
similar considerations make it clear that the purpose 
of the blood in living creatures is to provide them 
with nourishment ; and also why it is that when the 
blood is touehed it yields no sensation, as flesh does 
when it is touehed. Indeed, none of the residues 
yields any sensation either, nor does the nourishment. 
This difference of behaviour is because the blood is 
not continuous with the flesh nor conjoined to it 
organically : it just stands in the heart and in the 
blood-vessels like water in a jar. A description of 
the way in which the parts of the body derive their 
growth from the blood, and the diseussion of nourish- 
ment in general, comes more appropriately in the 
treatise on Generation a and elsewhere. For the 
present it is enough to have said that the purpose 
of the blood is to provide nourishment, that is to 
say, nourishment for the parts of the body. So 
much and no more is pertinent to our present 

IV. The blood of some animals contains what are The uniform 
called fibres ; the blood of others (e.g. the deer and ^ od*. 
the gazelle) does not. Blood which lacks fibres does 
not eongeal, for the following reason. Part of the 
blood is of a more watery nature, and therefore 
does not congeal ; while the other part, which is 
earthy, congeals as the fluid part evaporates off. 
The fibres are this earthy part. 

Now some of the animals whose blood is watery 
have a specially subtle intelligence.** This is due not 
to the coldness of their blood, but to its greater thin- 



350 fa „ 

Sid to Kadapov etvat- to yap yewoes ovSerepov €^€t 

tovtldv. €VKLvr)TOT€pav yap eypvoi T V V ctta^atv to, 
XeTTTorepav tyovra rrjv vyporrjra Kal KaOapcorepav. 
oid yap rovro Kal twv avalp.wv evia crvverwrepav eyei 
25 ttjv *pvxV v ^ V ^ (JL)V ival\iwv 3 KaOdirep eiprjTai 7Tp6repov, 
olov 7] fxeXirra Kal to yivog to twv \wp\xr\Kwv Kav 

CI Tl €T€pOV TOLOVTOV ioTIV . heiXoTepa TOL Xlav 

vSaTwSrj. 6 yap <j)6j3os /carai/ru^cr 7TpowSo7roirjTai 
ovv to) rrdOei tol TOia\)TJ\v k\ovTa tt\v iv Trj /capSta, 
so Kpaaiv to yap vSwp tw ipvxptp 7T7]kt6v ioTiv* 816 
Kal TaAAa to, aVai^ia SetXoTepa twv ivalpuov Igtiv 
ws OLTrXcog el7reiv } Kal aKLvrjTL^et Te (f)ofiovpL€va /cat 
TTpoteTai TT€piTT<x>\LaTa Kal fieTafidXAei evia Tag 
Xpoas avTwv. tol Se ttoXXcls e^pvTa Xlav tva$ Kal 
7ra)(€Las yewSeGTepa ttjv cJ)volv eari Kal BvpiwSrj to 
35 rjOos Kal iKCTaTLKa Sid tov Ovfiov. BepfJLOTrjTOS 
yap ttoitjtlkov 6 Ovjiog, tol Se OTeped 6ep[iavdeVTa 
651a jxaXXov OepjJLalvei twv vypwv al 8' Ives GTepeov Kal 
yew&es, woTe yivovTai olov irvplai iv tw aifiaTi 
Kal t.euiv TToiovaiv iv tols 9vyiols. Sto ol Tavpot Kal 
ol Kairpoi 6vpLcbo€Ls Kal iKGTaTLKol- to yap afjita 
tovtwv IvwoicTaTOVj Kal to ye tov Tavpov Ta^tcrra 
5 TrrjyvvTai irdvTwv. i^aipov\xevwv Se tovtwv twv 
Ivwv oi) TT-qyvvTai to alfxa' KaQdirep yap iK tttjXov 
el tls i^eXoL to yewSes ov 7rrfyvvTai to vowp, ovtw 
Kal to atfia' al yap tves yfjs. pbrj itjatpovfiivwv 

a At 648 a 2 ff. 

b For the connexion between fear and cold c/. 667 a 16, 
692 a 22 ff., and Rhetoric, 1389 b 30. 


ness and clarity, neither of which characteristics 
belongs to the earthy substance ; and an animal 
which has the thinner and clearer sort of fluid in it 
has also a more mobile faculty of sensation. This 
is why, as I said before, a some of the bloodless 
creatures have a more intelligent Soul than some 
of the blooded ones \ the bee and the ants 

and such insects. Those, however, that have ex- 
cessively watery blood are somewhat timorous. 
This is because water is congealed by cold ; and 
coldness also accompanies fear ; therefore in those 
creatures whose heart contains a predominantly 
watery blend, the way is already prepared for 
a timorous disposition.** This, too, is why, gener- 
ally speaking, the bloodless creatures are more 
timorous than the blooded ones and why they 
stand motionless when they are frightened and 
discharge their residues and (in some cases) change 
their colour. On the other side, there are the 
animals that have specially plentiful and thick 
fibres in their blood ; these are of an earthier 
nature, and are of a passionate temperament and 
liable to outbursts of passion. Passion produces heat ; 
and solids, when they have been heated, give off 
more heat than fluids. So the fibres, which are solid 
and earthy, become as it were embers inside the 
blood and cause it to boil up when the fits of passion 
come on. That is why bulls and boars are so liable 
to these fits of passion. Their blood is very fibrous ; 
indeed, that of the bull is the quickest of all to congeal. 
But just as when the earthy matter is taken out 
of mud, the water which remains does not congeal ; 
so when the fibres, which consist of earth, are taken 
out of the blood, it no longer congeals. If they are 



651 a 

Se TTrjyvvrai, otov vypd yrj vrro iftvxovs' rov yap 
Oepfiov vtto rov ipvxpov eKOXipopievov ovve^arpil^ei 

10 to vypov, KaBdrrep etprjraL nporepov, Kal urp/vvrai 
ov)( vtto Oepfiov dAA* vtto ipvxpov ^rjpaivoixevov. ev 
Se rots' owpiaoiv vypov iorc Std rrjv depfiorrjra ri)v 
ev rots £wois. 

HoXXcov S' eorlv atVta r) rov aifiarog <f>voi$ Kal 
Kara to rjGos rots* £tuots" Kal Kara, rr)v aloBrjoiv, 
evXoyws* vXrj yap eon iravrbs rov awfiarog' rj yap 

i5rpocj)rj vXf] y rd 0° cu/xa rj eoxdrrj rpocj^rj. rroXXrjv 
ovv TToieZ ota(f>opdv Oepfiov ov Kal ipvxpov Kal Xeirrov 
Kal Tra^i) Kal doXepov Kal Kadapov. iX^P ^* ^ GT ^ 
to voarwoes rod atpiaros Std ro [irynw 7rerre(f)6ai rj 
oiecfrdapdai, ware 6 pev i£ dvdyK7}$ i-X^P* ° ^' 
aipiaros X^P LV ^ (JT ^ V - 

20 V. HifjLeXrj oe /cat oreap oia<f)epovai fxev dXArjXwv 
Kara rr)v rov atpiaro^ Siacfropdv. eon yap eVa- 
repov avrwv atjita TTerrepLpevov St* evrpocjylav, Kal ro 
IXJ] KaravaXiGKopLevov eh ro oapKtuSes p,6piov rwv 
t^wwv, evrrerrrov Se Kal evr pace's*. hiqXol Se to 

25 XiTrapov avrwv rwv yap vypwv ro Xnrapov kolvov 
aepos Kal rrvpog eoriv. Std rovro ovSev e^et rwv 
dvat^ttov ovre mpeXrjV ovre oreap, on ouS' at/xa. 
rwv S' evaipiwv rd pev owpiarcoSes k'xovra ro af/xa 
oreap e^et pL&XXov. ro yap oreap yewSeg eon, Std 

° As it were, the " raw " material. 

b I have used the terms " lard " and u suet " rather than 
" soft fat " and " hard fat " because they represent more 
closely the distinction made by Aristotle. The difference 
between them is now known to be less fundamental, and is 


not taken out, it does congeal, as moist earth does 
under the influence of cold : the cold expels the heat 
and makes the fluid evaporate, as has been said 
before ; so it is due to the solidifying effect of 
the cold, and not of the hot, that what remains 
becomes congealed. And while it is in the body the 
blood is fluid on account of the heat which is there. 

There are many points both in regard to the tem- 
perament of animals and their power of sensation 
which are controlled by the character of the blood. 
This is what we should expect : for the blood is the 
material a of which the whole body consists — material 
in the case of living creatures being nourishment, and 
blood is the final form which the nourishment assumes. 
For this reason a great deal depends upon whether 
the blood be hot, cold, thin, thick, muddy, or clear. 
Serum is the watery part of blood ; and it is watery 
either because it has not yet undergone concoction or 
because it has been already corrupted ; consequently 
some of the serum is the result of a necessary process, 
and some is there for the purpose of producing blood. 

V. The difference between lard and suet b is parallel Lard and 
to a difference in the blood. They both consist of Suet * 
blood that has been concocted as the result of plentiful 
nourishment ; that is, the surplus blood that is not 
used up to nourish the fleshy parts of the animal, but 
is well concocted and well nourished. (This point 
is proved by their greasiness, for grease in fluids is 
a combination of Air and Fire.) This explains 
why there is no lard or suet in any of the bloodless 
animals. And among the others, those whose blood 
is denser tend to contain suet rather than lard. Suet 

due to varying proportions of unsaturated triglycerides and 
the lengths of the carbon chains. 



TTrjyi'VTCLL Kauarrep Kai to aifia to ivtuoes Kai avro 
Kal oi £a^not ol ToiovTOi' dXlyov yap ex €i vocltos, 

30 to oe ttoXv yrjs. Sio to, jjutj dfi(j>djoovTa dXXa 
KepaTcnorj GTeap ex^i. favepd 8* fj <f>vais avTWV 
rod tolovtov GTOix^iov TiX-qp-qs ovoa to) KepaTcborjs 
etvai Kal darpaydXovs e^etv drravTa yap £rjpa Kal 
yerjpa. -rqv <f>voiv ear (v. ra 8' dficbtuoovTa /cat 

35 aKepara Kal rroXvGxibrj TrifieXrjv eye 1 olvtl OTeaTos y 
fj ov TTTfyvvrai ovBe BpvnT<=Tai ^paLvofievri Sia to 
[IT] elvai yecohrj ttjv <j>voiv avrrjs. 

MeVpia [Lev ovv ravra ovra iv tois jiopiois tcov 
651 b £ojojv dxfreXet (rrpos [Lev yap aia9iqoiv ovk ifiTTOol^ei, 
Trpos 8' vyUiav Kal ovvafiiv ex €L jioYjdeiav), vrrep- 
fiaXXovTa he to) TrXrjBei c^delpet Kal jSAdVret. el 
yap Trav yevoiTO to GOJiia TrLLieXrj Kal Greap } airo- 
Aoit* dv. £wov jiev yap ion Kara to alodrjTLKOv 
5 fiopiov, fj he crapf Kal to dvdXoyov alodrjTiKOV to 
8* aljia, woTTep eip-QTai Kal npoTepov y ovk ey^ei 
aiodrjGLv, oto ovbe TriLLeXrj ovhe OTeap- atfia ydp 
7T err epLfievov Igtlv, coot el 7?av yevoiTO to awfia 
toiovtov, ovk dv e^oi ovhejiiav aiadrjaiv, Sto Kal 
yqpdoKei ~ayeu>s T(i Xlav irlova - dXlyaiiia yap are els 

io tt]v TiioTr\Ta dvaXiGKOiievov tov aiLiaTOs> ra 8' oAiy- 
atfia rjhrj Trpoajhorro ltjt ai Trpos tyjv <j)9opdv rj ydp 
<f>6opa oXiyaiLila tls €Gtl, Kal to SXlyaipuov 1 TraOrj- 


1 sic Th. : animal pauci sanguinis S: oXtyov vulg. 



is of an earthy character ; it contains but little 
water against a large proportion of earth ; so it 
congeals just as fibrous blood and broths do. So 
too the animals which have horns but have teeth 
in one jaw only contain suet. And it is clear that 
their natural constitution is full of this element 
(earth) from the fact that they have horns and huckle- 
bones, for they are all of them solid and earthy in 
constitution. On the other hand, the animals which 
have incisor teeth in both jaws and have toes (not 
uncloven hoofs), but no horns, contain lard instead 
of suet. Lard neither congeals nor splits up into 
small pieces when it dries, owing to the fact that 
it is not earthy. 

Lard and suet when present in the parts of animals 
in moderate quantities are beneficial : they do not 
hinder the action of the senses, and they contribute 
towards the health and strength of the body. But 
when the amount of them is excessive they are 
destructive and injurious. This is shown by the 
consideration that if the whole body were to become 
lard and suet, it would perish. The sine qua 7ion of a 
living creature is its sensory part, which is flesh or its 
counterpart : and since, as I have said before, blood 
is not sensitive, neither lard nor suet, which are just 
concocted blood, is sensitive. Therefore, if the whole 
body were to become either of these, it would have 
no sensation whatever. For this reason, too, unduly 
fat animals age quickly : their blood gets used up to 
produce fat, so there is very little of it left : and 
anything that has but little blood is well on the road 
to decav. In fact, decay is just a form of blood- 
deficiencv ; and an animal deficient in blood is 
easily susceptible to the effects of accidental cold and 




Kal ayovtorepa brj ra ttlovol Igti bid rrjv avrrjv 
alriav o yap ebei ihc rov alfiarog els rrjv yovrjv 

15 levai Kal to arrepfia, tout' els tt]v TTipLeXrjv dva- 
XiOKerai Kal to areap* rreTTopLevov yap to atfia 
ylverai ravra, ware t) oXtos ov yiverai i7epiTTto\.ia 
avrols ovbev rj oXtyov. 

Kat rrepl ^ev alp.aros Kal i^aipos Kal mpLeAfjs 
Kal arearoSy tL re ionv eKaarov avrcov Kal bid 
rivas alrlas, eiprjrai. 

20 VI. "Egti be Kal 6 fiveXds afyxards" tls (f>vois> Kal 
ovx warrep o'lovraL Tives, rrjg yovrjs aTTepfjLarLKTj 
bvvafjus. brjXoL o° ev tols veois rrdpLTrav are yap 
e£ alfiarog avveartorcvv rtov \xopitov Kal tt)s rpocpr/s 
ovgtjs tols ififSpvois aifiaros, Kal ev tols ogtols 6 

25 ptveXds alfJLarwhrjs eariv av^avofxevcov be Kal rrer- 
ToyLevajv, KaOdirep Kal rd [inpia [leTafidXXeL Kal rd 
cnrXdyvya rag XR oas {vTrep^oXfj yap al par cooes Kal 
tojv \j7rXdyyyujv eKaarov eariv en vecov ovtlov), 
ovtco Kal 6 pcveXos. 

Kat Tcvv fiev TTLfieXcootov Xirrapos Kal iriyLeXfi 
Sfioios, ooois Be firj TTipieXyj ofioiov 1 aAAa areap 

30 ywerai to atpta Trerro^evoVj tovtols be. aTeaTojbrjs . 
Sio toIs pitv Keparo(J)6poLS Kal firj dfic^wbovoi 
GrearcobrjSj tols S' dfJL(j>cobovGL Kal rroXvaxibeGL 
TTipLeXtohris . {rfKiora be tolovtos 6 pa^iT-qs eari 
fiveXos Sid to belv avTov eivai owe^f] Kal biex^v 
bid TTdarjs rrjs pa^ecos" bL7]prjpLevrjs Kara tovs 

35 atfrovbvXovs- Xiuapos 8' cov rj oTeaTcobrjs ovk dv 
ofxoLcos TjV ovvexrjs, dAA' t) Opavaros fj vypos) 
1 ofiotov Z 1 : ojxotos alii. 

a e.g. secretion of semen. See above, on 647 b 27. 
b Plato, Timaeus, 73 c. 



heat. The same eause is responsible for the com- 
parative sterility of fat animals : that part of the 
blood which ought to go to form semen and seed gets 
used up in forming lard and suet, which are formed 
by the coneoetion of blood. Henee in fat animals 
there is either no residue a at all, or else very little. 

I have now spoken of blood, serum, lard and suet, 
describing the nature and the Causes of each of them. 

VI. Marrow, again, is really a form of blood, and not. Marrow, 
as some 6 think, the same as the seminal substance 
of the seed. This is proved by the ease of very young 
animals. In the embryo, the parts are composed out 
of blood and its nourishment is blood ; so it is not 
surprising that the marrow in the bones has a blood- 
like appearance. As they grow and beeome mature/ 
the marrow ehanges its colour just like the other parts e 
of the body and the viscera, which while the creature 
is young all have a blood-like appearance owing to the 
large quantity of blood in them. 

Animals which contain lard have greasy marrow, 
like lard ; those whose concocted blood produces not 
a substanee like lard but suet have suety marrow. 
Hence, in the horned animals which have teeth in 
one jaw onlv the marrow is suety. and in the animals 
that have teeth in both jaws and are polydactylous it 
is like lard. (The spinal marrow cannot possibly be 
of this nature because it has to be continuous and 
to pass without a break right through the whole 
spine which is divided into separate vertebrae ; and if 
it were fatty or suety it eould not hold together as 
well as it does, but it would be either brittle or fluid.) 

c Dynamis. See Introduction, pp. 30 ff. arid note on 646 a U. 
d Lit. " are concocted." 
a A good instance of Aristotle's usage of the term " part." 



e51b , , v , , 

v Evta S' ovk I'^et twv £aja>v (bs agLWS eirreiv 

yive\6vy ovojv ra Sara laxvpa /cat irvKvd, olov ra 

&52&TOV Xeovros' tovtov yap ra oard, Std to TrdfiTrav 

darjiiov e'xetv, So/cei oi)/c e^ei^ oAa>? /LiueAdv. eVet 

Se tt^v /itey tcDv octtcov avdyKf] cjyvviv virapx^v tols 

Repots rj to dvdXoyov tols ootols, olov tols ivvopoLs 

5 rrjv CLKavOav, dvayKaiov ivloLs vTrapx^w koX fiveXov, 

ifiTrepLXafjL^avoiievrjs rrjs rpo^s e£ rjs yiverat ra 

6o~ra. on §' rj rpo<f>7) ttclgiv at/xa, ctprjraL irpo- 

repov. evXoycos Se /cat arearcoSeLS of fiveXol /cat 

Tri^ieAtoSets" €io~lv Std yap ttjv aXiav ttjv yivo\iivr]v 

V7TO TOV 7T€pl€X€<j9ai TOLS Octrois 7T€TT€T0LL TO OUfia, 

10 rj Se /ca#' avro treipLS atfiaros areap /cat TripLeXr} 


laxvpa evXoycos iv tols fiev ovk eveoTi, tols S' 
oXlyos 1 ev€GTiv m els yap ra outol avaXlaKeTai rj 

'Ev Se to is firj €x ovatv OGTa dAA' aKavOav 6 
paxLTTjs fiovos earl fiveXos' dAtyat/xd t€ yap cfrvoec 
15 VTrdpx^ ovTa, /cat kolXt] a/cavffa [lovov rj ttis pd- 
X^ws euTLV. St6 ev Tavrrj eyylveraL- \iovr) tc yap 
e^et xwp av > Kai P-ovrf Setrat avvSeapiov Std tols 
OLaXrjifjeLS . Std /cat d evravda pLveX6s> coairep 
etprjTat, dXAoLOTepos eVrtv Std to d^Tt Trepovrjs 
1 dAiyots per errorem Bekker. 



Some animals have no marrow worth mentioning : 
these are they whose bones are strong and close- 
textured : for instance, the Lion, whose bones eon- 
tain so insignificant an amount of marrow that they 
look as if they contained none at all. Now in view of 
the fact that the bodies of animals must have in them 
either bones or the counterpart of bones (e.g. the 
spines in water-animals), it follows of necessity that 
some of them must contain marrow as well, due to the 
enclosing of the nourishment out of which the bones 
are formed. Now we have stated already that the 
nourishment of all the parts of the body is blood. 
And it is quite reasonable that the various sorts of 
marrow should be suety and lardy ; because the 
blood undergoes concoction owing to the heat pro- 
duced by its being surrounded by bone, and the 
product of blood when it undergoes concoction by 
itself is suet and lard. And also, of the animals that 
have strong, close-textured bones, some have no 
marrow, others have but little, and this is reasonable 
too, because the nourishment gets used up to supply 
the substance of the bones themselves. 

In those animals that have no bones but spine 
instead, the backbone contains the only marrow they 
possess. It is the nature of these creatures to have 
but a small amount of blood, and their only hollow 
spine is that of the backbone. Therefore the marrow 
is formed in it — indeed, it is the only bone where 
there is room for the marrow, and the only one 
which requires something to connect it together, 
owing to its being divided up into segments. 
This also explains why the marrow here is (as 
I have already said) somewhat different from the 
marrow elsewhere. It has to serve as a fastening, 



652 a 

yap yiveudai yXtcrxpog, /cat vevpcbhrjs eorlv Iv 
€XW tcloiv. 

20 Ata, rt \iev ovv pcveXbv k\ei ra £<£>a ra k'xovra 
piveX6v } eipr]r at- /cat Tt eartv o /xueAos*, £k tovtojv 
(f)av€pov, on rrjs alpianKrjs rpo^rjg rfjs ets Sard 
/cat aKOLvOav pie pi^o peeves eorl to epLirepiXapL^avo- 

pi€VOV 7T€pLTTCDpLa 7T€<f)Q4v. 

VII. ITept 8' £yK€(f)dXov u^hov ear iv £)(6pL€vov 

25 €L7T€LV TToXXoLS ydp /Cat O £yK€(f>aXoS OOK€L pLVeXoS 

etvat /cat apx^ tou pveXov Sta to avveyr] T ° v 
paxtrrjv avrti) opdv piveXov. eon he rrdv rovvavnov 
avro) rr\v (f>vaLv <hs etVety 6 pev yap eyt<e<j)o,Xos 
ifjvxporarov tqjv ev rep atopan pLoptcov, 6 he piveXos 
Qeppios tt]v <f)V<jLv hrjXo? 8' 7] Xiiraporris avrov /cat 

30 to ttiov. 8to /cat avvexrjs 6 pavtV^s" tw eyKec/)dXcp 
eurLv del yap rj <f)vcn$ pcqxavdrac Trpos rr\v eKaarov 
virepfioXrjv ftorjdeiav rrjv rod evavrlov rrapehplav, Iva 
dvLud^rj rrjv Oarepov vrrepfioXrjv Oarepov. on pier 
ovv 6 pveXos Beppios 1 early hrjXov £k ttoXXwv. rj he 

35 rod eyKe<f)dXov ifsvxporr^s <f)avepd p,ev Kal Kara rrjv 
dL^LVy en 8' dvatpLorarov rtov vypcov rwv ev rw 
Gwpari Trdvrcov (ou8' onovv yap aepcarog e'xei ev 
652 b avrw) /cat avx^porarov . eon 8' ovre Treplrrcopia 
ovre rcov ovvexwv pLOplcov, dXXa tStos" rj (fivcnsy /cat 
evXoycvs rotavrrj. on pev ovv ovk e^et ovvex^tav 
ovheplav rrpos ra alcrOrjTLKa popia, hrjXov pcev /cat 
5 Sta rrjs oijjecoSi en he pidXXov ra> prjheplav rroieiv 
atadrjaiv Qiyyavop^evos, touTrep ovhe to at/xa ovhe to 
TTeplrraJpia rcov ^cocov. 

1 dtp/ios PZ : Oepfxov vulg. 



and so it is sticky ; and it is sinewy too so that it 
can stretch. 

We have now explained why marrow is present in 
certain animals. We have also made clear what 
marrow is. The surplus of the blood-like nourishment 
which is distributed to the bones and spine gets 
enclosed within them, and after it has undergone 
concoction then it is marrow. 

VII. The brain is the next subject on our list. It Brain, 
comes appropriately after the marrow, as many think 
that the brain is really marrow a and is the source of 
the marrow, because, as observation shows, the spinal 
marrow is continuous with the brain. As a matter 
of fact, however, the two are quite opposite in nature. 
The brain is the coldest of all the parts in the body, 
whereas the marrow is hot, as is shown by the fact 
that it is greasy and fat. And that is the real reason 
why the spinal marrow is continuous with the brain. 
Nature is always contriving to set next to anything 
that is excessive a reinforcement of the opposite sub- 
stance, so that the one may level out the excess of 
the other. Now there are many indications that the 
marrow is hot ; and the coldness of the brain is 
shown not only by its being cold to the touch, but 
also by its being the driest of all the fluid parts of the 
body and the one that has the least blood in it — in 
fact, it has none at all. It is, however, not a residue, 
nor is it to be classed among the parts that are con- 
tinuous. It is peculiar in its nature, and this after all 
is but reasonable. Inspection shows that the brain 
has no continuity with the sensory parts, but this is 
shown still more unmistakably by the fact that like 
the blood and the residue of animals it produces no 
sensation when it is touched. 

a Cf. Plato, Timaeus 75 c, D. 



652 b 

f Y77apX€t Se TOt? £tpOl$ TTpOS T7]V T7)S <f>VOeO)$ 

oXt)$ aaJTTjplav. ol \xev yap tov ^coov ryv ifjvxrjv 
TiOeacri Trvp rj TOiavrrjv riva Svvajj.iv, c/yopriKcog 
TiOevTes' fiiXriov 8' tocos' <f>dvai iv rotovrcp rivl 
10 awfian ovveoTavai. tovtov 8' aiVtov otl Tots' rrjs 

\jjW)(r\S €pyOl$ V7TTIp€TLK(I)TaTOV TO)V aeo/xaTGOv TO 

Oepfjiov iariv to rp4cf)€Lv yap Kal KLvelv ipvxrjs 
k'pyov earl, ravra oe 8ta ravrrjs ^dXiara ylverai 
rrjg ovvdfiewg. ojjlolov ovv to ttjv \fjvxr)v elvai 
(fydvai Trvp Kal to TrpLova rj rpviravov tov reKrova 

15 TTjv reKrovLKTjv, otl to epyov TrepalveTaL eyyvs 
dXArjXajv ovaiv. otl {iev ovv OeppLOTrjros tol £<£>a 
pL€T€X €LV dvayKalov, SrjXov eV tovtojv eirel 8' 
duavra Selrat rrjs evavrias poTrrjs, tva Tvyyavr\ tov 
fierplov f<al tov fiecrov (tt)v ydp ovcrlav k\eL tovto 
Kal tov X6yov } tqjv 8' ai<pa)v ei<drepov ovk €X €L 

20 x^pk)* 0La t^vttjv tt]v ahlav 77pos* tov rrjg KapSlas 


iyKe<f>aXov r) <f)vuis ) Kal tovtov X^P lv virapx^L tovto 

TO fJLOpLOV TOt? £,0)01$, TTjV (f>VGLV e^OV KOLVTjV voaTo? 

Kal yr)$ y Kal Std tovto rd (juey) 1 evaifia I'^et irdvra 
eyKecfraXov, tcov 8' dXXajv ovSev cos* elirelv, 7rXr)v otl 

25 Kara to dvdXoyov, oiov 6 ttoXvttovs' SXiyoOepfia yap 
irdvTa 8td rr)v dvaLfilav. 

f O {lev ovv iyKe<f)aXo$ evKparov rroLeX tt)v ev Tjj 
Kapola OepjjLOTTjTa Kal t^eaiv iva Se Kal tovto to 
jjioptov Tvyxdvrj jieTpias depfioTrjTos, d<^' eKarepas 
ttjs (f)Xef36s, Trjs Te fieydXrjs Kal rfjs KaXovpLevrjs 

80 dopT-qs, TeXevTtoaiv at <f>Xefies els ttjv fii]VLyya ttjv 

1 (ii€v) Rackham. 

a e.g. Democritus ; see Aristotle, Be anima, 403 b 31. 
6 Or, " proportion." 



The brain is present in order to preserve the animal 
organism as a whole. Some a maintain that the Soul 
of an animal is Fire or some such substance. This is 
a crude way of putting it ; and might be improved 
upon by saying that the Soul subsists in some body 
of a fiery nature. The reason for this is that the 
hot substance is the most serviceable of all for the 
activities of the Soul, since one of the activities of 
the Soul is to nourish ; another is to cause motion ; 
and these are most readily effected by means of 
this substance (viz. the hot). So to say that the 
Soul is fire is like saying that the craftsman, or his 
craft, is the saw or the auger which he uses, on 
the ground that the activity is performed while the 
two are near together. From what we have said this 
at any rate is clear : animals must of necessity have in 
them a certain amount of heat. Now, everything needs 
something to counterbalance it, so that it may achieve 
moderation and the mean ; for it is the mean, and 
not either of the extremes apart, which has re- 
ality and rationality. 6 For this cause nature has 
contrived the brain to counterbalance the region of 
the heart and the heat in it ; and that is why animals 
have a brain, the composition of which is a combina- 
tion of Water and Earth. Hence, although all 
blooded animals have a brain, practically none of 
the others has (unless it be just a counterpart, as 
in the case of the Octopus), for since they lack blood 
they have but little heat. 

The brain, then, makes the heat and the boiling in 
the heart well blent and tempered ; yet in order that 
the brain may still have a moderate heat, blood- 
vessels run from the great Blood-vessel and what is 
known as the Aorta, till they reach the membrane 



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1 (kcli) Rackham. 
2 doXepov coai. Buss, (turbidi 2) : itoXXov vulg. 



which surrounds the brain. And in order to prevent 
injury being done through heat, the blood-vessels 
surrounding it are not few and large but small and 
multitudinous ; and the blood is not muddy and 
thick but thin and clear. This also explains why 
fluxes begin in the head ; they occur when the 
parts around the brain are colder than the rightly- 
proportioned blend. a What happens is that, as the 
nourishment exhales upwards through the blood- 
vessels, the residue from it becomes cooled owing 
to the specific nature of the brain, and produces 
fluxes of phlegm and serum. And we should be justi- 
fied in maintaining that this process resembles, on 
a small scale, the one which produces rain-showers. 
Damp vapour exhales up from the earth and is carried 
into the upper regions by the heat ; and when it 
reaches the cold air up aloft, it condenses back again 
into water owing to the cold, and pours down to- 
wards the earth. However, so far as Natural Philo- 
sophy is concerned with these matters, the proper 
place to speak of them is in the Origins of Diseases. *> 
Furthermore, it is the brain (or, if there is no brain, 
its counterpart) which produces sleep in animals. 
It cools the onflow of blood which comes from the 
food (or else is due to other causes of the same sort), 
and weighs down the part where it is (that is why 
when a person is sleepy his head is weighed down), 
and causes the hot substance to escape below to- 
gether with the blood. Hence, the blood accumu- 
lates unduly in the lower region of the body and 
produces sleep ; at the same time it takes away 
from those animals whose nature is to stand upright 
the power to do so, and the others it prevents from 
a See p. 38. b No such treatise exists. 



653 a ^ 

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to avTod epyov, aAA' rj ov ipv^et rj 7rrj{j€i, cuore 

See De somno, 455 b 28 ff., especially 456 b 17 ff. 
b The cranial bone, which covers the anterior fontanelle. 


holding their heads upriglit. These matters have 
been spoken of separately in the treatises on Sensation 
and on Sleep. a 

I said the brain is compounded of Water and 
Earth. This is shown by what happens when it is 
boiled. Then it becomes solid and hard : the earthy 
substance is left behind after the Water has evapor- 
ated owing to the heat. It is just what happens 
when pulse and other forms of fruit are boiled ; they 
also get hard and earthy altogether, because the 
greater part of them is earth, and the fluid mixed 
with it departs when they are boiled. 

Of all the animals, man has the largest brain for 
his size ; and men have a larger brain than women. 
In both cases the largeness is due to there being a 
great deal of heat and blood in the region around the 
heart and the lung. This too explains why man is 
the only animal that stands upright. As the hot sub- 
stance prevails in the body it induces growth, begin- 
ning from the centre along its own line of travel. 
It is against great heat, then, that a large supply of 
fluid and cold is provided. This bulk of moisture 
is also the reason why the bone that surrounds the 
brain (called by some the bregma) b is the last of all 
to solidify ; the hot substance takes a long time to 
evaporate it off. This phenomenon does not occur 
in any other of the blooded animals. Again, man 
has more sutures in the skull than any other animal, 
and males have more than females. The size of the 
brain is the reason for this also ; it is to secure 
ventilation, and the larger the brain, the more 
ventilation it requires. If the brain becomes unduly 
fluid or unduly solid, it will not perform its proper 
function, but will either fail to cool the blood or else 




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* At De gen. an. 722 a, 776 a 15 ff. 



will make it set fast, thus producing various forms of 
disease, madness, and death. Indeed, the heat that 
is in the heart, being the source, is extremely re- 
sponsive to any influence upon it ; and if the blood 
which surrounds the brain undergoes any change or 
any other affection, then this heat at once becomes 
sensitive of it. 

We may now claim to have considered all the fluids 
which are present in animal bodies from their very 
earliest stages. There are others which are first 
produced only at some latter stage, and among these 
we must reckon the residues of the nourishment — 
that is to say, the deposits from the bladder and 
from the gut ; and also semen, and milk ; these 
make their appearance according to the species and 
sex of the animal concerned. Discussion of the resi- 
dues of the nourishment will come in appropriately 
during our general consideration and examination 
of nourishment ; we shall then show in what animals 
they occur, and why the} r do so. Semen, which 
gives rise to generation, and milk, which exists on 
account of generation, we shall deal with in the 
treatise on Generation. 0, 

VIII. We must now go on to consider the rest of Flesh and 
the uniform parts. Let us take first of all Flesh (and, Bone ' 
where Flesh is absent, its counterpart), for this is to 
animals both a principle and a body in itself. Its 
primacy can also be logically shown, as follows. We 
define an animal as something that has the power of 
sensation, and chiefly the primary sensation, which 
is touch ; and the organ through which this sensation 
is effected is the flesh (or its counterpart). And 
flesh is either its primary organ (comparable to the 
pupil in the case of sight), or else it is the organ and 



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° Apparently because the objects with which it deals are 
more " corporeal " than those of the other senses — it has 
to be in bodily contact with them. 

b As apart from a priori reasoning. 

c Sometimes, as here, '* counterpart " could be represented 
by the modern term " analogue." 
d Lit., " the soft-shelled creatures." 



the medium of the sensation combined in one (com- 
parable to the pupil phis the whole of the transparent 
medium in the case of sight). Now not only was it 
pointless, it was impossible for Nature to make such 
a combination in the case of the other senses ; with 
touch, however, it was due to necessity, since its 
sense-organ is the only one which is corporeal — 
or at least it is definitely the most corporeal one. a 
It is also clear from our actual experience in sensation b 
that all the other parts exist for the sake of the organ 
of touch (the flesh). In these I include the bones, the 
skin, the sinews, the blood-vessels ; also the hair, nails 
of every sort and kind, and the like. The bones, 
for instance, which are hard in substance, have been 
devised for the preservation of the soft parts. The 
same is true of the counterpart c of the bones in other 
creatures : two examples in species of fish are spine 
and cartilage. 

Now with some animals this hard supporting 
substance is situated inside the body, with others 
(some of the bloodless ones) it is outside. It is out- 
side in the case of all the Crustacea d (e.g. the Crabs 
and the group of Crayfish), and the group of Testacea e 
too, e.g. those that are known as Oysters. All these 
have their fleshy part inside, and the earthy part 
which holds it together and protects it is out- 
side — outside, because it performs an additional 
function as well : since these creatures are bloodless, 
they possess but little heat, and the shell acts like 
a couvre-feu ; it encloses the faintly burning heat 
and protects it. Another quite different group of 
creatures, the Turtles and the group of freshwater 

* Lit., "the shell-skinned creatures." " Testacea " is the 
nearest modern term. See Introduction, p. 23. 




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3 to Piatt: ra vulg. 4 (yivos) Piatt. 



Tortoises, are apparently in like case. On the other 
hand, the Insects and the Ccphalopods are differ- 
ently constructed from these, as -well as being 
different from each other. Not only, as it appears, 
have they no bony part, but they have practically 
no earthy part at all distinct from the rest of the 
body. The Cephalopods are almost wholly soft 
and fleshy, yet in order to prevent their bodies 
from being easily destructible as fleshy struc- 
tures are, the substance of which they are formed 
is intermediate between flesh and sinew, having the 
softness of flesh and the elasticity of sinew. When 
it is split up, it breaks as flesh does, that is, not 
longitudinally but into circular portions. The reason 
for this seems to be that such a structure secures 
the greatest strength. There is found also in these 
creatures the counterpart of the spinous bones of 
fishes ; examples are : the " pounce " (os sepiae) of 
the cuttlefish, and the " pen " (gladius) of the 
calamaries. Nothing of this sort, however, appears 
in the Octopuses : this is because in them what is 
called the " head " forms but a small sac, whereas 
in the cuttlefish and calamaries the " head " is of 
considerable length. So we see that, in order to 
secure that they should be straight and inflexible, 
nature prescribed for them this hard support, just 
as she gave to the blooded creatures bones or spines. 
Quite a different contrivance obtains in the Insects — 
different both from the Cephalopods and from the 
blooded creatures, as has already been stated. In 
the Insects we do not find the clear-cut distinction 
of hard parts and soft ; here, the whole body is hard, 
yet its hardness is such that it is more fleshlike than 



654 a 

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bone is and more bony and earthy than flesh. The 
purpose of this is to ensure that the body shall not 
easily break up. 

IX. The system of the bones is similar to that of Bonea. 
the blood-vessels : each is a connected system begin- 
ning from one point. There is no such thing as a 
bone by itself in isolation ; every bone is either 
actually part of the connected scheme, or else is 
attached to it and so is in contact with it. This 
enables Nature to use any couple of bones either 
as a single connected piece, or, when flexion is 
required, as two distinct pieces. In like manner, 
there is no such thing as a blood-vessel by itself in 
isolation : they are all of them parts of one blood- 
vessel. An isolated bone could never discharge the 
function for which all bones exist ; for, being dis- 
continuous and disconnected from the rest, it could 
never serve as the means either for bending or for 
straightening a limb ; but worse than that, it would 
be a source of harm, like a thorn or an arrow sticking 
in the flesh. Similarly, if we imagine a blood-vessel 
isolated and not connected with the source of them 
all, it could never keep the blood within it in a proper 
condition, since it is the heat which comes from that 
source which prevents the blood from congealing, as 
is shown by the putrefaction of blood when separ- 
ated from it. This source of the blood-vessels 
is of course the heart, and the corresponding source 
of the bones in all bony species is what is called the 
backbone. The system of the bones is a connected 
whole, starting from the backbone, since the back- 
bone connects together the length of the animals 
body and holds it straight. Now although this back- 
bone is a unity because it is connected together, it 

f2 163 


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tva ylvryraL KapapLS Kal €ktolgis (dXXws yap r) oXcos 
aSvvarov, rj ov kclXws av €ttolovv rrjv TOiavrrjv kl- 
vrjfjLv)' eVta S' avrajv opLolav e^ovra rrjv dpx?)v T7 ) v 
25 Oarepov rfj reXevrfj darepov [avvSeSerat vevpois]' 3 
Kal xovhpwhr) ok jiopia pL€Ta£v tcov Kapufiewv 
iariv,* otov cToifir}, TTpos to dXXrjXa (jlt) rpifieiv. 

Yiepl ok rd oord at odpKes TrepLrre^vKaGi, 
7Tpoa€LXrjjjijjL€vaL XeiTTots Kal IvwSeai Secr/xots" oov 


so TrXaTTOVTts €K rrrjXov t,tpov rj twos dXXrjs vypas 
avGTacreoJs vj>LGTaoi toov GTepeoov ti GOJjiaTOJv, eW' 


8eor)[jUovpyr)K€v €K twv aapKtov to t,coov. tols 

35 ydplV) TOLS 8* aKLVTJTOLS <f)vXaKrjs €V€K€V > otoV at 

655 a GvyKXelovGaL irXevpal TO GTTjOoS GCOTrjplaS x^P LV 

1 rd Peck : ras Z : $ vulg. : oard tcov uoptcov iariv ras fiev 
jih> vulg.) e^ei T( * KojXa km. xdfxifiiv Z. 

2 tols SU : re vulg. : ye EY. 

3 11. 16-25: hunc locum correxi, partim S et Albertum 
secutus. vid. p. 46. fortasse et eW S' dvdyKt) . . . cnov 
bvXcov (11. 14-16) secludenda. 

4 eiatv vulg. 



is also a thing of many parts because of its division 
into vertebrae, since the body must be able to bend 
while the animal is in motion. And the bones of the 
various limbs (in those animals which have them) 
are connected with this backbone, from which they 
originate. Some of them have extremities which fit 
on to each other : either (a) one is hollow and the 
other rounded, or (6) both are hollow and hold a 
huckle-bone between them (as it might be a bolt), 
to admit of bending and extension, since these 
movements would be quite impossible or at any rate 
unsatisfactory without such an arrangement, (c) 
There are some joints in which the adjacent ends of 
the two bones are similar in shape ; [these are bound 
together by sinews,] and there are pieces of cartilage 
inserted in between them, like a pad, to prevent 
them from rubbing against each other. 

Now the whole system of the bones exists to sub- 
serve the fleshy parts of the body, which have their 
place around the bones and are attached to them by 
thin fibrous threads. Modellers who set out to mould 
an animal out of clay or some other plastic substance 
begin first of all with a hard and solid core and mould 
their figure round it. Nature's method has been the 
same in fashioning animals out of flesh. With one 
exception, all the fleshy parts have a core of bone : 
for the parts that move and bend, this is present as 
a means for enabling the limb to bend ; for those 
that do not move, it serves as a protection : an 
example of this are the ribs, enclosing the chest, 
which are a means of protection for the viscera in 

a The text of this paragraph has been confused by a 
number of interpolations, most of which I have omitted in 



twv Trepl T7]v KaphLav GTrXdyxvwv ra he 7repl ttjv 
KOiXlav dvoarea k&olv, oitws firj KwXvrj rrfv av- 
olBrjdLV ttjv diro rrjg Tpo</>r)s yivofievrjv tols ^wols 
i£ dvdyKfjs Kal tols OrjXecn rrjv ev avrots twv e/x- 
fipvwv av^rjGLv. 

5 Ta [lev ovv ^lootokcl twv c^wwv Kal ev avrdlg /cat 
eKTOs 7Tapa7rXr}crLav e^et rrjv twv ootwv hvvap.LV /cat 
laxypdv. ttoXv yap pe[£w irdvTa ret toiclvtcl twv 
firj l^wotokwv <h$ /cara Xoyov elirelv twv ow\xaTWV 
eviaxov yap ttoXXol ytVerat jxeydXa twv l^wotokwv , 

10 olov ev Aifivr) Kal rot? tottols tols Oeppols /cat rot? 
^Tjpols. tols he fieydXoLs loxvpOTepwv Set twv 
V7T€petafiaTWV Kal fiei^ovwv Kal o~K.Xr)poTepwv 3 /cat 


dppevwv OKXrjpoTepa rj tcl twv drjXeiwv, /cat ra twv 
aapKO<f>dywv (rj Tpo<f>rj yap hid {idx^jS tovtols), 
wanep Ta tov XeovTos' ovtw yap e^et raura 

15 GKXrjpdv ttjv cf)V(Jiv wut e^diTTeaOaL TVUTopevwv 
KaBduep e/c XlOwv irvp. e^et ^€ Ka ^ ° heX<f>ls ovk 
aKavOas dXX ootcl' ^wotokos ydp euTiv. 

Tots §' evaifjiois fxev firj l^wotokols he nap- 
aAAarret /cara fiiKpov rj <f)VULS } olov tols opvioiv 
ogtol fieVj doBeveoTepa he. twv S' IxOvwv tols jxev 

20 wotokols dKavOa, Kal tols 6<f>eoLv aKavOwhrjs iarlv 
rf twv ootwv (fyvcrLS, ttXtjv tols Atav pteyaXoLS' tov- 


laxvv loxvpOTepwv Set twv OTepewpbaTwv. Ta Se 
KaXovpieva creAa^ x ov &P° LKav @ a T V V 4 >V ' <JLV coro'* 
vypoTepav Te yap dvayKalov avTwv elvai ttjv k'l- 

° Cartilaginous fishes, including the sharks. 



the region of the heart. The exception is the parts 
near the belly, which in all animals are boneless. 
The purpose of this is that the swelling which takes 
place of necessity after the receipt of nourishment 
may not be hampered, and (in females) to prevent 
any interference with the growth of the fetus. 

The nature of the bones is similar in all viviparous 
animals (that is, internally viviparous as well as 
externally) ; and as the Vivipara are much larger 
proportionately in bodily size than other animals, 
their bones are strong. In some places many of these 
animals grow to a great size, as for example in Libya 
and other hot dry countries. These large animals 
need stronger and bigger and harder supports, 
especially those of them that are particularly violent 
in their habits. Hence, the bones of males are harder 
than the bones of females, and those of carnivorous 
animals than those of herbivorous, because the car- 
nivorous have to fight for their food. An example 
is the Lion : it has such hard bones that when they 
are struck fire is kindled as it is from stones. Note 
that the Dolphin, being viviparous, has bones like the 
other viviparous creatures, and not fish-spines. 

In the creatures which though blooded are not 
viviparous Nature has made a series of graduated 
changes : for example, birds have bones, but they 
are weaker than the bones of the Vivipara. The 
oviparous fishes have fish-spine, not bone ; and the 
serpents have bone whose nature is that of fish-spine ; 
except the very large species, and they have bones, 
because (just like the Vivipara) if their bodies are 
to be strong the solid framework of them must be 
stronger. The creatures called Selachia a have spines 
made of cartilage. This is because their movement 



655 a 

25 vqaiv, ware Set /cat rrjv ra>v epeiGfxdrcov firj Kpav- 
pov etvai dXXa fiaXaKwrepav, Kal to yewhes els 
to Sep/xa ttSLv dvrjXojKev rj (f>vot$' dfia he rrjv avTrjv 
V7T€poxr)v elg ttoXXovs tottovs dhvvcLTei hiavefieiv 7) 
(f>VGiS. eveori he Kal ev tol$ ^cootokois 7roAAa rcov 
oartov xovopdior] } ev ooois av}JL(f>epei jiaXaKOV etvat 

so /cat fxv^woes 1 to orepeov hid rrjv adpKa rrjv irepi- 
Keifievrjv, olov GVfifiefirjKe irepl re ra wra /cat 
rovs fjLVKrfjpas' Opaverat yap ra Kpavpa raxecos 
ev roTs a7Texovoiv, -q he envois rj avrr] x ov $P ov 
/cat ogtov eoTi, oia(f>epeL he. ra> fiaXXov /cat rjrrov 
Sto /cat ovherepov avtjdvercu d7TOK07rev. 

85 Ot fxev ovv ev rois Tre^ocs djiveXoi ^oVSpot /C€^a>- 
piGpLevcp fiveXa)' to yap x a) P L £°f JL€V0V € ^ a7Tav 
fjuefjuypLevov fiaXaKrjv iroiel Kal [jlv^coStj 2 rrjv rod 
Xovopov GVGraGLV. ev oe to is GeXdxeGcv rj pdx^s 
655 b x ov $P<a>07}$ \xev eGTtv, exei oe fxveXov dvr ogtov 
yap avTots V7rdpxei tovto to fiopiov. 

Hvveyyvs he Kara rrjv d<f>rjv eon rots ogtols /cat 
rd TOidSe rwv fioplwv, olov ovvxes t€ /cat oVAat /cat 
X^Aat /cat KepaTa Kal pvyxV Ta T &> v opvtBcov. iravra 
5 he Tavra fiorjdetas ex ovaL X^P LV [ T( * ^ ( ? a ] 3 ' T( * 7^P 
avTCJV GvveGTTjKOTa oXa Kal ovvcbvufia rots fioplois, 
olov ottXti re oXrj Kal Kepas 6Xov } \ieprrfxdvr\T ai irpds 
TTjv GOJrrjplav e/caaTOts 1 . ev tovtco he tw yevei Kal 

1 ^D/xaiSc? Z. 2 ^vfuvhrj EPSZ. 

3 [ra £a>a] secludit Rackham. 

° Cf. the " law of organic equivalents." 
b See note on 644 a 17. 



has to be somewhat supple, and accordingly the 
supporting framework of their bodies must be some- 
what pliable, not brittle. In addition, Nature cannot 
allot the same plentiful supply of any one substance 
to many different parts of the body ; a and in the case 
of the Selachia she has used up all the available earthy 
substance in constructing their skin. In the Vivipara 
too there are many instances of cartilaginous bones : 
they are found where it is an advantage that the 
solid framework should be pliable and glutinous for 
the benefit of the flesh that surrounds them. This 
applies to the ears and the nostrils. Such projecting 
parts quickly get broken if they are brittle. Car- 
tilage and bone are the same in kind and differ 
only by " the more and less " b ; so neither of them 
continues to grow when it has been cut out of the 
living organism. 

The cartilages of land-animals contain no marrow — 
that is, no marrow existing as a separate thing. 
What in ordinary bones is separable is here mixed 
in with the body of the cartilage and gives it its 
pliable and glutinous character. In the Selachia, 
however, although the backbone is cartilaginous it 
contains marrow, because it stands to these creatures 
in place of a bone. 

The following substances or " parts " resemble 
bones very closely as regards their feel : the various 
sorts of nail ; hoof and talon ; horn, and beak. 
All these substances are present for the sake of self- 
defence. This is shown by the fact that the complete 
structures which are made out of them and bear the 
same names — e.g. the complete hoof, or horn — have 
been contrived in each case by Nature for the creature's 
self-preservation. We must reekon the teeth in this 



655 b 

rj twv oZovtwv earl <j>vois, rots p,ev VTrdpxovGa 

10 TTpog ev epyov rrjv rfjs Tpo<f>rjs ipyaaiav, rot? oe 
Ttpos re tovto Kal rrpog aXtcqv, otov toXs tfap^ap- 
oSovgl Kal ^avXiohovoi ttvlgiv. e£ avdyKrjs Se 
7T(xvra ravra yewSrj Kal orepeav k'xet rrjv <f)VGiv 
ottXov yap avrrj SvvapLig. Sto Kal irdvTa rd rocavra 
fiaXXov ev rots rerpd7TOGtv virdpyei Repots twv 

15 ^wotokwv, Sta to yecoSeorepav ^X €lv ^dvra rrjv 
ovaraaiv rj to twv dvOpwTrwv yevos. aXXd Kal 
Trepl tovtwv Kal twv i^opLevajv, otov Seppiaros Kal 
KVGTecos 1 Kal vpievos Kal Tpiywv k<u Trrepwv Kal 
twv dvdXoyov tovtois Kal el ri tolovtov eart puzpos, 
VGTepov a/xa rots dvopLoiopepeGL Bewpryreov rrjv 

20 acTiav avrwv, koI tlvos eveKev V7rdp)(ei tols £>wois 
eKaoTOV eK twv epywv yap yvwpc^eiv, wGirep 
KaKetva, Kal ravra avayKalov dv eir). dAA' on 
avvwvvpia tols oXols rd peprj, ttjv Ta^iv direXafiev 
ev rots opLotopLepeGL vvv. €lgI S* dpxal irdvTWv 
tovtwv to re ogtovv Kal rj Gap£. en he Trepl 
yovrjs Kal ydXaKTog aTreXiTropev ev rfj Trepl twv 

25 vypwv Kal opLOiopiepwv Oewpia' toIs yap Trepl 
yeveGews Xoyoig appidrrovGav e)(ei tt)v GKeiptv to 
p,ev yap avTwv apx*) to oe Tpocfyrj twv yivGptevwv 

X. Nt>v oe Xeywptev olov a7r' dpxrjs TrdXcv, dp£d- 
fievoL irpwTOV drro twv rrpwTWV. tt aai yap Tocg 

1 okvt€o$ Buss, {gkvtccos EY). 



class too. In some creatures teetli are present to 
discharge one function only — viz. mastication ; in 
others they are a means of force as well (e.g. 
sawlike teeth and tusks). All these parts are 
of necessity earthy and solid in character ; that 
is the proper sort of substance for a weapon. 
So there is a tendency for all parts of this sort to 
appear in the four-footed Vivipara more extensively 
than in man, because the former all have more earthy 
matter in their constitution. We shall, however, con- 
sider these substances, and the other kindred ones 
such as skin, bladder, membrane, hair, feather, and 
the counterparts of them, and all such parts, when 
we come to deal with the non-uniform parts. Then 
also we shall consider the Causes of them and for 
what purpose each of them is present in animal bodies ; 
since it is true to say, of both sets of things, that our 
knowledge of them must be derived from a study of 
the functions which they discharge. The reason why 
we have just been taking them with the uniform 
substances and out of their proper order is that in 
them the name of the complete structure is the same 
as that of a portion of it, and also because the sources 
and principles of them all are bone and flesh. We 
also left out all mention of semen and milk when we 
were considering the fluid uniform substances. As 
semen is the source of the things that are generated 
and milk is the food that feeds them, the proper place 
to discuss these is in the treatise dealing with 

X. We may now make what is practically a fresh The non. 
beginning. We will begin first of all with the things ™j f ™ 
that come first in importance. 



so £>cpois rots reXeiois 1 Svo ra dvayKaiorara piopta 
iarcv, fj re oexovrai rrjv rpo<f>r)v Kal fj to neplrra)[ia 
a<f)iaoiv 2 ' ovre yap elvai ovre av^dveaOai cvSe^TCU 
dvev Tpo<f)rjs. (ra fxev ovv <f>vrd—Kal yap ravra tfqv 
(frapiev — rod fiev dxprjarov Trepirraj fxaros ovk k'xei 

35 T07TOV €K TTjS yrjs ydp AajlfidveL 7T€7TeiipL€VY}V rrjv 

Tpo<f)rjv, dvrl de tovtov 7Tpoterai ra GTrepfiara /cat 
tous" Kapirovg.) rplrov oe fiepos ev ndaLv eon to 
toutojv fiicrov, iv a> r) dpx^ eariv r) rrjg ^ajrjs. r) 

656 a fl€V OVV TtDV <f)VTO)V (j)VOLS OVOCL flOVlflOS OV 7ToXv- 

eiSrjs ear i ra>v dvopoiopeptov' TTpos yap 6XLya$ 
irpd^eis dXlyaiv dpydvwv r) ^p^o-ts" Sto deojpiqreov 
Ka9* avrd 7T€pl rrj$ ISiag avrchv, ra be npog rco 
Xjqv alaOrjGLV e\ovra TroXvpLopcf)orepav e^et rr)v 
5 toeav, Kal rovrajv erepa irpd Irlpwv pc&XXov, Kal 
TToXvxovuripav oawv fir] piovov rod tfiv dXXd Kal 
rod ev ^rjv r) <f)vcris fierelArj^ev. roiodro 8' earl to 
ra)v dv9pa)7TO)v yevos* rj ydp puovov pcerex^i rod 
6eiov ra>v r)puv yvwpipiwv t > d>a)v ) rj pcdXiara rrdvrayv, 
ware oid re rodro } Kal Sid to yvdtpipiov elvai 
10 fidXiar avrov rr)v ra>v e^wQev fioplajv pLop^rjv, 
Trepl rovrov XeKreov 7Tpcorov. ev9vs ydp Kal rd 
<f>vaei fiopca Kara cfrvcriv exei rovrco fiovtp, Kal to 

1 toTs TeAeiot? Peck : rocs ye r. Ogle : Kal reAeioufievois Kal 
reXeiois Piatt : Kal TeAeiot? vulg. 

2 a<f>iaotv SUY : a<f>rjaovotv alii. 

° These three parts of the " perfect " animals are again 
referred to at De juv, et sen, 468 a 13 ff. At Be gen, an, 



An animal can neither exist nor grow without food. 
Therefore in all living creatures of perfect formation a 
there are two parts most necessary above all : one by 
which food is taken in and the other by which residues 
are eliminated. (Plants — which also we include 
under the head of living things — have, it is true, no 
place for the useless residue, but this is because their 
food, which they get out of the earth, is already con- 
cocted before it enters them, and instead of this 
residue they yield their fruit and seeds.) And in all 
creatures there is a third part intermediate between 
these indispensable two, and this is the seat of the 
source and principle of life. Plants, again, are so made 
as to remain in one place, and thus they do not exhibit 
a great variety of non-uniform substances; they have 
few actions to perform, and therefore but few organs 
are needed to perform them. For this reason we must 
consider plants and their formations separately. But 
with creatures that not only live but also have the 
power of sensation, the formations are more varied, 
and there is more diversity in some than in others, the 
greatest variety being found in those creatures which 
in addition to living have the capability of living the 
good life, as man has. Man is the only one of the 
animals known to us who has something of the divine 
in him, or if there are others, he has most. This is 
one reason why we ought to speak about man first, 
and another is that the shape of his external parts is 
better known than that of other animals. Another and 
obvious reason is that in man and in man alone do the 
natural parts appear in their natural situation : the 

733 b 1 and 737 b 16, 26, the " perfect " animals are the 
viviparous ones. For the " most highly finished " animals 
see 666 a 28. 



rovrov dvco 77/50? to rod oAov e'^et avor jxovov yap 


To pi€V OVV €)(€IV TTjV K€tf>aAr}V daapKOV €K TCOV 

16 7Tepl rov iyhcitpaAov elprjfjLdvcov dvayKalov crvfi- 
PefirjKev. ov yap coanep rives Aiyovoiv, on ei 
GapKcbBiqs rjv, ixaKpofiicbrepov dv rjv to yevos, 
dAA' evaiaOrjacas eveKev doapKov elval cpaacv 
aloddveGQai {lev yap rep iyK€tf>dAcp } rrjv 8' aLodrjuLV 
ov TTpouUoOai rd piopia ra oapKcohrj Atav. rovrcov 

20 8* ovoerepov iuriv dArjOes, aAAa iroXvaapKos [xev 
6 tottos cov 6 7T€pl tov iyKecpaXov rovvavrlov dv 
aTTtipyd^TO ov eW/ca vnapx^i rots' £>cpois 6 iy- 
KetpaXos (ov yap dv iSvvaro Karaifjvx^v dXeacvcov 
avros Xiav), rcov r alaOfjaecov ovk alrios ovhepLias, 
os ye avaioO'qros Kal avros ionv cootrep oriovv 

25 rcov TrepiTTtojidTiDV . dXX ovx evpLoKovres oca 
rlva alriav eVtat rcov atoOrjoecov iv rfj KetpaXfj 
rots ^cools etat, rovro 8* opcovres lotaLrepov ov 
rcov dXXcov piopLcuv, e/c avAAoytofiov irpos dAXrfXa 
ovv$vdt,ovoLV. on /xev ovv dpxrj tcov aloOfjaecov 
iuriv 6 irepl rrjv Kapocav tokos, hicopiarai irpo- 
repov iv rocs Trepl aloOrjaecos, Kal Slotl at fiev Svo 

so cf>av€pd)S rjprrjfievaL Trpos rrjv Kapotav cdalv, rj re 
rcov arrrcov Kal r) rcov ^vpcov, rcov Se rpicov rj pikv 
rrjs 6atf>pr)a€cos p<€crr}, aKorj 8e /cat o0ts* pdXiar iv 
rfj KecpaXfj 8ta rrjv rcov aloOrjrrjplcov tfrvaiv elai, Kal 

a See the identical phrase in Be resp. 477 a 22* 
b Cf. Plato, Timaeus 75 a-c. 



upper part of man is placed towards the upper part 
of the universe.* 1 In other words, man is the only 
animal that stands upright. 

In man, the head is lacking in flesh, and this follows of the 
of necessity from what we have said about the brain. 
Some b say (erroneously) that if the head abounded Sense- 
with flesh mankind's lifespan would be longer than or s ans 
it is, and they explain the absence of flesh as on pur- 
pose to facilitate sensation, their view being that the 
brain is the organ of sensation, and that sensation 
cannot penetrate parts that are too fleshy. Neither 
of these assertions is true. The truth is that if 
the part surrounding the brain were fleshy, the 
effect of the brain would be the very reverse 
of that for which it is intended : it would be 
unable to cool the rest of the body because it would 
be too hot itself. And, of course, the brain is not 
responsible for any of the sensations at all ; it has no 
more power of sensation than any of the residues. 
People adopt these erroneous views because they are 
unable to discover the reason why some of the senses 
are placed in the head ; but they see that the head 
is a somewhat unusual part, compared with the rest, 
so they put two and two together and argue that 
the brain is the seat of sensation. The correct view, 
that the seat and source of sensation is the region 
of the heart, has already been set forth in the treatise 
Of Sensation? where also I show why it is that two of 
the senses, touch and taste, are evidently connected 
to the heart ; of the remaining three, smell is placed 
between the other two, hearing and sight, and these 
are practically always located in the head : this is 
owing to the nature of the organs through which 

c De sensu, 438 b 25 ff. 



656 a 

TOVTQJV T) OlpLS TraCTLV' €77€L Tj y OLKOTJ Kdl TJ 0<J(f)prjCFLS 

35 errl rGiv lydvtov Kal tlov tolovtojv Troiei to Xeyo- 
pevov cfyavepov olkovovgl piev yap Kal da^palvovraij 
alaOrjrrjpiov 8' ovoev e^ovai <f>avep6v ev rfj Ke<f)aXfj 
rovrtov tqjv alaOrjrcbv. 1 r) 8' Sift is rraai Tots' e^ovaiv 
656 b evX6ya>s earl irepi rov eyKe<ftaXov 6 piev yap vypos 
Kal xpvxpoSy rj 8' vhwp rrjv (ftvaiv early rovro yap 
tojv oiacftavcov eixftvXaKrorarov eanv. en oe rag 
aKpifiearepas rd>v alaOrjaewv oid tcov KaOaptorepov 
i)(6vrcov to atpa poplwv dvayKaiov aKpifiearepag 
5 ylveaOai' eKKOTrrei yap r) rrjs ev rep alfiarc 9ep- 
pLorrfros KLvrfais rrjv alaOrjriKrjv evepyeiav oid 
r auras rds air las ev rfj KecftaXfj rovrcov ra ataOrj- 
rrjpid ear iv. 

v piovov o eari to epLrrpoauev aaapKov, aAAa to 
omaOev rrjs KecftaXrjs, 8td to iraai rots eypvaiv 
avrrjv dpdorarov oeiv elvai rovro to piopiov ovSev 

10 yap opOovaBai ovvarai (ftoprlov eyov, rjv 8* av 
TOiovroVy el aeaapKOjpevrjv et^e rrjv KecftaXrjv. fj Kal 
SrjXov on ov rrjs rod eyKe<ftdXov aiaOrjaeojs X^P LV 
aaapKos r) KecftaXrj eanv to ydp oiriaQev ovk e^et 
iyKecftaXov, daapKov 8' 6pLolo)s. 
"E^ei 8e Kal rrjv aKorjv evXoyws evia tcov ^cpwv 

15 ev rtp totto) rep rrepl rr)v Ke(ftaXrjv to yap Kevbv 
KaXovpievov depos rrXrjpes ean, to Se rrjs aKorjs 
alaOrjrrjpLov depos elval (ftapiev. 

1 (eVet . . . aladriTuiv) Cook Wilson, qui et (ou) post 
Aeyo^ew, 1. 35. 


they operate. Sight is always located there. The 
case of hearing and smell in fishes and the like 
shows that the opinion I maintain is patently correct. 
These creatures hear and smell, although they have 
no obvious and visible organs for these senses in the 
head. As for sight, it is reasonable enough that 
when present it should always be located near the 
brain, for the brain is fluid and cold, and the sense- 
organ of sight is identical in its nature with water, 
which of all transparent substances is the easiest to 
keep confined. Again, those senses which are in- 
tended for more precise work than the others must 
necessarily receive greater precision by being situ- 
ated in parts where the blood is specially pure, since 
the movement of the heat in the blood ousts the 
activity appropriate to sensation. These are the 
reasons why the organs of these senses are placed in 
the head. 

Now the back of the head is free from fleshiness as 
well as the front. This is because the head is the 
part which all animals that possess one have to hold 
as upright as possible. Nothing that carries a burden 
can raise itself upright, and the head would be 
burdened if it were well covered with flesh. And 
this is another reason to show that the lack of flesh 
on the head is not for the purpose of enabling the 
brain to function in sensation. There is no brain in 
the back of the head, although the back has no more 
flesh on it than the front. 

Some animals have their organ of hearing as well 
as of sight located in the region of the head. This is 
well explained on our view, which is that the organ 
of hearing is of air. The space in the head called the 
vacuum is full of air. 



'Ek /Ltev o?v tcDv S(f)0 aXpiojv oi rropot cf)ipovuiv eis* 
tcl? rrepl tov iyK€(f>aXov <f)X4 flas- 7raAiv 8' e/c ra)v 
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["EoTt 8' out' dvaitiov ovSev alaOrjTiKov ovTe to 

20 at/xa, dAAd Tcuy e/c tovtov ti. hiorrep ovSev iv 
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atfia 1 - ovSev yap twv ^cpcvv (jioptov.] 2 

"E^et 8' iv to) efirrpoaOev tov iyKe<f)aXov rrdvTa 
rd eypvTa tovto to piopiov, Sid to epjrrpouBev 
etvai icj> y o aloddveTai, ttjv 8* atcrOrjaiv diro ttjs 

25 KapScaSt TavTrjv 8* etvai iv tois* epiTTpooOev, Kal 
to aloOdveaOac 8id tqjv ivalpLWv ylveaOat fjioplcuv, 
<f?Xefia)v 8* etvai K€v6v to omudev kvtos. reVa/crat 
8e tov Tponov tovtov Tct, aladrjTrjpia Tjj cj>vuei 
KaXcbg, rd fiev ttjs aKorjg irrl pLecrrjs tt)s" 7Tepi<f>epeia$ 
(aKovet, yap ov piovov /car' evOvcvplav dXXd irdv- 

80 ToOev), r] 8' oxjjis els to epLrrpooOev (Spa yap KaT 
evOvojplav, rj Se Ktvrjois els to e^irrpooOev, irpoopav 
Be Bel i(f>* o rj klvtjols). rj Be Trjs OG(f)prjGecos 
fi€Ta£v to)V opLfxaTtov evXoycos. BirrXovv pcev yap 
ioTiv €KauTov tujv alo6r]Tr]puov Bid to BirrXovv 
etvai to acu^a, to [lev Be£i6v to 8' dpiUTepov. errl 

85 JU^f o5v TTJS d<j)7]S TOVT dBrjXoV TOVTOV 8* CLlTtOV 

OTi ovk eoTi to irpwTOV aloOrjrrjpiov rj adp£ Kal to 

TOiOVTOV fAOpiOV, dXX ivTO$ . ilTi Be T7]S yXcOTTTJS 

tjttov fiiv, fiaXXov 8' r} irrl Trjs d(f>rjs' eoTi yap otov 

1 ovV avro to atfia om. E. 

* 11. 10-22 seclusi (20-22 Ogle) : partim ex 666 a 16 trans- 

a This passage seems to be a note on a remark which comes 
a few lines below, and should probably be omitted from the 
text. Part of it is taken from 666 a 16. 



Passages (or channels) run from the eyes to the 
blood-vessels that are round the brain. And, again, 
a passage runs from the ears and connects to the 
back of the brain. 

[No bloodless part is capable of sensation, nor 
indeed is the blood itself. It is the parts which are 
made out of blood that have this faculty. Hence, 
in the blooded animals, no bloodless part is capable 
of sensation, nor indeed is the blood itself, for it is 
no part of animals.] a 

The brain, whenever there is one, is in the forepart 
of the head. This is (a) because all acts of sensation 
take place in a forward direction ; (b) because the 
heart, from which sensation has its origin, is in the 
forepart of the body ; and (c) because the process 
of sensation depends upon parts that have blood 
in them, whereas the sac at the back of the head 
contains no blood-vessels at all. In fact, Nature 
has located the sense-organs in a very satisfactory 
manner. The ears arc half-way round the circum- 
ference of the head, because they are to hear sounds 
from all directions alike and not only from straight 
before them. The eyes face front : this is because 
sight is along one straight line, and we must be able 
to see along the line in which we are moving, which 
is directly forward. The nostrils are between the 
eyes, and this is quite reasonable. Each of the 
sense-organs is double, because the body itself is 
double : it has a right side and a left side. It must 
be admitted that this duality is not at all clear in the 
case of touch : this is because the primary sense- 
organ of touch is not the flesh or a corresponding part, 
but something internal. With the tongue the duality 
is not very clear, but more so than with touch. 



657 a a(j>rj rt$ Kal avrrj rj aluQrjais. ofiws §e orjXov Kal 
€ttl ravT'qs' <f>aLV€TCLi yap iGx^ptivrj. eVt Se tojv 
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otfieprjS' cord re yap ovo Kal opLpLara Kal rj tojv 
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5 TpOTTOV K€Lfl€VT) Kal 0L€G7TaGpi€Vr] 3 Ka9a7T€p Tj TTjS 

CLKorjs, ovk av eVoiet to avrrjs epyov, ov8e to 
fiopiov iv w £gtlv Std yap rfjs dva7rvorjs r) aladrjuis 
rots exovoL fivKTrjpas, rovro Se to fiopiov /card 
fii.GOV Kal iv rois efxrrpoGdiv ianv. StoVep els 
fxiaov tojv rpicov aloBrjrrjpCwv ovvrjyayev rj <j>vois 
10 tovs jXVKTrjpaS) otov iirl Grddfxrfv decaa fiiav iul tt)v 
rfjs avaiTVorjs Kivrjoiv. 

\\aXws Se Kal rois dXXois l^et ravra rd ala8rj- 

TTjpia £(1)01$ TTpOS TTjV IhtaV <f)VGlV iKaOTOJ. XI. 

rd fji€v yap rerpaTrooa d7Trjprr}fiiva e^et rd (bra Kal 
dvaodev twv dfifidrajv, ojs So^etev dv y ovk e^et Se, 
15 dAAd (paCveTac Std to firj 6p9d eivai rd £a)a dAAd 


fjL€T€a)poT€pd t ovra Kal Kivovfxeva* Se'^eTcu yap 
GTpe<f>6fieva rrdvToOev tovs ip6(f)ovs fiaXAov. 


rrjv tov oipjxaTOS GKXrjp6rr]Ta Kal to k\eiv 
20 rpix^s dAAd TTrepwrd eivar ovk ovv e^ei Toiavrrjv 
vXrjv i£ rjs av eirXaoe Ta wTa. ofioiojs Se Kal tojv 

° Aristotle seems to refer here to the forked tongues of 
certain animals. See 660 b 7 ff. 


(Taste, in fact, is itself, as it were, a sort of touch.) 
The duality is plain, however, even with this sense, 
for it is seen to be divided. With the other senses, 
the organ is more evidently parted into two : there 
are two ears and two eyes, and two passages for the 
nostrils in the nose. The sense of smell, if it had 
been otherwise placed — separated into two, that is, 
like the sense of hearing — would not have been 
able to perform its proper function ; nor would 
that part of the body in which it is situated, since 
in animals which have nostrils, the sensation of 
smell is effected by means of inspiration, and this 
part is at the front and in the middle. This is 
why Nature has brought the nostrils together in a 
straight line and made them the central of the three 
sense-organs in the head, located where the motion 
of in-breathing takes place. 

In the other animals as well as in man these sense- Ears, 
organs are very satisfactorily arranged as required 
by the peculiar nature of each animal. XI. For 
instance, the quadrupeds have ears that stand out free 
from the head, and they are higher than the eyes — 
or appear to be, although this is not really so : it is 
an illusion due to the fact that these animals are not 
upright but stand on all fours. And as they are 
usually in this posture when in motion, it is useful for 
them to have their ears well up in the air, and also 
movable : this enables them to be turned round and 
oick up sounds better from all directions. 

XIL Birds have the auditory passages only, 
owing to the hardness of their skin, and because 
they have feathers instead of hair, which means that 
they have not got the right material for forming 
ears. The same argument applies to those oviparous 



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dpfioaec /cat eV €K€lvcov Xoyos. ex eL ^ KCLl V 


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e^etv aiTiov to vypd rd o^juara efvat tva d£u 


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1 om. Z 1 . 2 toutou yLtey ou^] rot; /xev o&> eu EPZ. 

a Or, " imperfectly developed." C/. Bk. III. ch. viii. 


quadrupeds which have horny scales. One vivi- 
parous animal, the Seal, has no ears but only auditory 
passages ; but this is because, though a quadruped, 
it is deformed. 

XIII. Man, the Birds, and the Quadrupeds (both Eyes, 
viviparous and oviparous) have a protective covering 
for their eyes. The viviparous quadrupeds have 
two eyelids to each eye (which also enable them 
to blink) ; some of the birds, especially the heavily 
built ones, and the oviparous quadrupeds, when 
they close their eyes, do so with the lower eyelid ; 
birds, however, can blink, with the aid of a mem- 
brane that comes out of the corner of the eye. The 
reason for the existence of these protective cover- 
ings is that the eye is fluid in order to ensure 
keenness of vision. If the eye had been con- 
structed with a hard skin it would of course have 
been less liable to injury by impact from without, 
but its vision would have been duller. For this 
cause the skin round the pupil is left thin and fine, 
and the safety of the eye is ensured by the addition 
of the eyelids. The movement of the eyelids known 
as blinking is a natural and instinctive one, not 
dependent on the will, and its object is to prevent 
things from getting into the eyes. All animals 
that have eyelids do it, but human beings blink 
most of all, because they have the thinnest and 
finest skin. 

Now the eyelid is encased with skin ; and that is 
why, like the tip of the foreskin, it will not unite 
again once it has been cut, because both of them 
are skin and contain no flesh. 

We said just now that some birds and the ovi- 
parous quadrupeds close the eye with the lower 



7 b 

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roov (horoKOJV <f>oXiScord e'ortv* ravra Se uKXrjpo- 
repa rrdvra rpi^og, (Lure Kal ra Sepfiara rod 
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ionv avroiSy StoVeo ovk e^ei, fiXi^apov eKeWev, 

15 to Se KarcoOev oapKwoes, war 9 e'xetv r ° fiXecfyapov 
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7rXayiov LiaX)iov. 

Ta Se rerpaTToSa Kal (horoKa ov GKaphapivrrei 
olloIws, on oi3S' vypdv avrois dvayKalov e^^tv Kal 
aKpifirj rrjv oipiv eVtyetots* ovgiv roTs 8' opviotv 

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jidXiara rwv opveajv els vijjo$), ra 8' liriy -eta Kal 
jirj TTTrjTiKa, olov dXeKrpvoves Kal ra roiavra, 


eyelid only. This is due to the hardness of the 
skin which surrounds the head, (a) The heavily 
built birds are not great fliers, and so the material 
which would have supplied growth for the wings has 
been diverted, resulting in thickness of the skin. 
These creatures, then, use only the bottom eyelid to 
cover the eye ; whereas pigeons and such use both 
eyelids. (b) With regard to, the oviparous quad- 
rupeds : As the horny scales with which they are 
covered are in every case harder than hair, so their 
skin also is harder than ordinary skin. And as the 
skin on their heads is hard, they can have no upper 
eyelid ; but lower down the skin has some flesh with 
it, and so they have a lower eyelid that is thin and 

Now the heavily built birds blink not with this 
lower eyelid, because its motion is slow, but with 
the membrane above mentioned, whose motion is 
swift, as is requisite. This blinking or nictitating 
begins at the corner of the eye nearest the nostrils, 
because it is better that the membranes should have 
one place of origin rather than two, and in these birds 
this is where the eye and nostril are conjoined ; also, 
the front is more a place of origin than the side. 

The oviparous quadrupeds do not blink in this 
way, because, unlike birds, which have to use their 
eyes over great distances, they go upon the ground, 
and therefore there is no need for them to have 
fluid eyes or great accuracy of sight. The crook- 
taloned birds are sharp-sighted, for they view their 
prey from above, and that also explains why they 
fly to a greater height than other birds. The 
birds that remain on the ground, however, and do 
not fly much (e.g. barn-door fowls and the like) are 



657 b 

ovk o^vwird* ovSev yap avra, KareireLyzi irpos 

TOV fiiOV. 

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ovoev ov yap e^ovGL rpt^as". irepl yap tov GTpov- 


1 tt^v Ogle: Kal vulg. : ttjv ante epyaaiav vulg., om, SU. 

PARTS OF ANIMALS, II. xiii.-xiv. 

not sharp-sighted, since there is no urgent necessity 
for it in their kind of life. 

Many differences in the eye itself are found among 
the Fishes, the Insects and the hard-skinned Crus- 
tacea, though not one of them has eyelids. In the 
hard-skinned Crustacea there cannot be an eyelid at 
all, for the action of an eyelid depends upon swift 
working of the skin. To compensate for the lack 
of this protection, all these creatures have hard 
eyes : it is as though the eyelid were all of a piece 
with the eyeball, and the creature looked through 
the lid as well. But since the vision is bound to be 
dimmed by this hardness of the eye, Nature has 
given the Insects (and even more noticeably the 
Crustacea) movable eyes, just as she has given some 
quadrupeds movable ears ; this is to enable them 
to turn towards the light and catch its rays and so 
to quicken their vision. Fish have fluid e} T es for the 
following reason. They move about a good deal and 
have to use their siffht over Ions: distances. Now 
when land-animals do this, they are looking through 
air, which is highly transparent ; but fish move about 
in water, which is inimical to sharpness of vision ; so 
to counteract its opacity their eyes are fluid in 
composition. At the same time, water contains far 
fewer objects to strike against the eyes than the air 
does ; hence fish need no eyelids, and because 
Nature never makes anything without a purpose, 
they have none. 

XIV. Those animals that have hair on their body Eyelashes 
have eyelashes on their eyelids : the others (birds and Hair ' 
and the creatures with horny scales) have none. 
There is one exception to this rule : the Libyan 
ostrich, which has eyelashes. The cause of this 

g 187 


658 a 

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1 -npavks delet Piatt. 


will be explained later. a Man is the only animal 
which has eyelashes on both lids. Why is this ? 
The quadrupeds tend to have more hair on their 
backs than on the underside of the body ; but in 
man the reverse is true. The purpose of hair is to 
give protection ; and as the quadrupeds go on all 
fours, they need more protection on their backs ; so 
they have no hair on their front, although the front 
is the nobler of the two sides. Man goes upright, 
and so there is nothing to choose as regards his need 
of protection between front and back. Therefore 
Nature has prescribed the protection for the nobler 
side, the front — an example of how, out of given 
conditions, she is always the cause of that which is 
the better. This, then, is why none of the quad- 
rupeds has lower eyelashes (though some have a 
few scattered hairs growing on the lower eyelid), 
or hair in the axillae or on the pubes, as man has. 
Instead of this, some of them have thick hair all 
over the back part of 6 their body (e.g. dogs), some 
of them have a mane (e.g. horses and such), others 
a flowing mane, like the male lion. Again, if an 
animal has a tail of any length, Nature decks that 
with hair too ; long hair for tails with a short stem 
(e.g. horses), short hair for tails with a long stem. 
This, however, is not independent of the general 
condition of the whole animal, for Nature gives 
something to one part of the body only after she 
has taken it from another part. So when she has 
made an animal's body extremely hairy, we find 
that there is not much hair about the tail. An 
example of this is the Bears. 

• See 697 b 13 ff. 
b Piatt deletes " the back part of." 


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10 fjL&Xiora, to S' evavrlws %X 0V drraOecrrepov euriv. 
'AAAa. nepl pi€V rovrwv TTapeKfirjvai crvpifiefirjKev 
ixofJievoLS rrjs irepl rag fiXe<j)aplBas alrias, Bid rrjv 
crvyyevetav avrwv, ware nepl rwv Xolttwv ev rots 
olk€lols Katpols diroBoreov rrjv [Avetav. 

XV. At S' 6(f)pv€s Kai at f$Xe</)apiBes dfJL(j)6r€pai 

15 fioTjOetas X^P LV ^laiv, at fiev 6<f>pves rwv i<ara- 
fiawovrwv vypwv, ottws aTroareywaiv otov aTioyeL- 
ocofjia rwv arrd rrjs Ke<f>aXfjs vypwv, at Be fiXecf)apiBes 
rwv Trpos rd opLfiara rrpoa'niTTrovrwv eveKev, otov 
rd x a P aKc ^l xaTa ttolovctl rives TTpd rwv epy\xdrwv} 
elal S' at p,ev 6<f>pves eirl avvOeaei oorwv, Bid Kal 

20 Baavvovrac ttoXXols aTroyrjpdaKovaiv ovrcos ware 
Beiodai Kovp&s- at Be /3Xe<f)apiBes eirl Trepan 
<f)Xefilwv s fi yap rd Beppca irepaivei, /cat to. (j)Xepia 

1 epy/xarcov scrips i : ipyfiaTcov Bekker : ipvixdrwv editores. 

This is one of the passages fastened upon by Bacon in 
his tirade against the importation of final causes into physics, 
Adv. of Learning (publ. 1605), ii. pp. 29, 30 : " This I finde 
done not onely by Plato, who euer ancreth vppon that shoare, 
but by Aristotle, Galen, and others, who do vsually likewise 
fall vppon these flatts of discoursing causes ; For to say that 
the haires of the Eye-liddes are for a quic-sette and fence about 



Man has the hairiest head of all the animals. This 
is (a) due to necessity, because the brain is fluid, and 
the skull has many sutures ; and a large outgrowth 
necessarily oecurs where there is a large amount of 
fluid and hot substance. But also (2>) it is on purpose 
to give protection ; that is, the hair affords shelter 
both from excessive cold and from excessive heat. 
The human brain is the biggest and the most fluid 
of all brains ; therefore it needs the greatest amount 
of protection. A very fluid thing is very liable both 
to violent heating and violent cooling, while sub- 
stances of an opposite nature are less liable to such 

This, however, is a digression. We were led into it 
because the subject was connected with our investi- 
gation of the cause of eyelashes. Anything further 
that there is to be said about it will be said in its 
proper place. 

XV. Both eyebrows and eyelashes exist to afford 
protection to the eyes : the eyebrows, like the eaves 
of a house, are to protect the eyes from the fluids 
that run down from the head ; the eyelashes are like 
the palisades which are sometimes put up in front of 
an enclosure ; their purpose is to keep out things that 
try to get in. a However, the eyebrows are placed 
where two bones join (which is why they often get so 
thick in old age that they have to be cut) ; and the eye- 
lashes are placed at the ends of small blood-vessels, 
which have to stop where the skin itself eomes to 

the Sight . . . and the like, is well inquired & collected in 
Metaphisicke, but in Phisicke they are impertinent." But 
there is no incompatibility, p. 33, *' For the cause rendred 
that the halves about the Eye-liddes are for the safeguard of the 
sight, doth not impugne the cause rendred, that Pilositie is 
incident to Orifices of Moisture" See also Xen. Mem. i. 4. 6. 



658 b 

7T€pas e'^et rod pLYjKovs' coot dvayKatov Sta. rrjv 
OLTnovaav t/c/xaSa ocopLaTLKrjv ovoav, av firf rt rrjs 
<f>v<j€Cos epyov ipL7ro$iorj jrpos dXXrjv xprjaiv, /cat 
25 Sta rr)v TOiavTiqv air lav i£ dvdyKTjs iv rots* roirots 
tovtois ylvzoOai rpt^as 1 . 

XVI. Tot? fl€V OVV dXAoLS £,tl>OlS TOLS rerpGLTTOGL 

/cat ^cootokols ov 7r6ppo) rponov rivd SiioTrjKev 
dXXrjXwv to rrjs oocfrpriGecos alaOrjTrjpLov, dXX* ooa 

30 \xkv e^et TTpopLrjKeis elg orevov dTrrjypiivag rds 
oiayovas, iv ra> KaXovfiivw pvyxti /cat to tcov 
fiVKTrjpwv ivvTrdpx^L fiopiov Kara t6v ivSexofxevov 
Tponovy toIs S' dXXois jxaXXov SirjpOpcopivov iorl 
TTpos Tas criayovas. 6 S' iXi<f)ag t'StatVarov e^et 
tovto to popiov twv dXXcov ^tocov to T€ yap 

35 fxeyeOos /cat tt)v Bvvapiv e^et TrepiTTrjv. jjlvkttjp 
ydp ioTiv a> ttjv rpo(f>rjv irpoodyeTai, KaOdnep X €L P^ L 
€59 a xp^pievos, rrpog to oropLa, ttjv t€ £r}pav /cat ttjv 
vypdv, /cat ra SevSpa TTtpLtXiTTtov dvaoira, /cat 
XprjraL Kaddntp av el X €L P^' T V V Y®-P < f>v (Jlv cAtoSes' 
a/xa to £a>6V ion /cat ire^ov, ajar' eVet ttjv Tpo<f>rjv 
it; vypov ovvifiaivev £X eiv > dvairveiv S' dvayKatov 
6 ne^ov ov /cat evaipLov, /cat ptrj ra^etav irotelodai ttjv 
pLCTapoXrjv e/c tov vypov rrpos to ^r\pov ) KaOdrrep 
evia twv ^cootokojv /cat ivalpcov /cat dvo.7TV€ ovtojv, 
to yap fxiyeOos ov vnepfiaXXov, dvayKatov dfiolcog 
rjV xPV (J ^ aL T( i ) vyptp (jjarrep /cat Trj yfj. olov ovv 


io TTopl^ovraty iva ttoXvv xpovov iv Trj OaXdrrrj p.i- 
vovt€S e'A/ca>otv €^co0€v tov vypov Sta, rod opydvov 


yeOos i7TOLrjo€ rots* iXi<f>acnv. StoVep dvairviovow 
Or " strength." 



an end. Thus, owing to the fact that the moisture 
which comes off is corporeal in composition, hair must 
be formed at these places even on account of a neces- 
sary cause such as this, unless some function of Nature 
impedes by diverting the moisture to another use. 

XVI. The general run of viviparous quadrupeds Nostrils, 
differ very little among themselves as regards the 
organ of smell. The following variations occur, how- 
ever. Those animals whose jaws project forward and 
become gradually narrower, forming what is called 
a snout, have the organ of smell in their snout — this 
being the only possibility ; in the others, the jaws 
and nostrils are more definitely separated. The 
elephant's nose is unique owing to its enormous size 
and its extraordinary character. By means of his 
nose, as if it were a hand, the elephant conveys 
his food, both solid and fluid, to his mouth ; by 
means of it he tears up trees, by winding it round 
them. In fact, he uses it for all purposes as if it 
were a hand. This is because the elephant has a 
double character : he is a land-animal, but he also 
lives in swamps. He has to get his food from the 
water ; yet he has to breathe, because he is a land- 
animal and has blood ; owing to his enormous size, 
however s he cannot transfer himself quickly from the 
water on to the land, as do quite a number of blooded 
viviparous animals that breathe ; hence he has to be 
equally at home on land and in the water. Some 
divers, when they go down into the sea, provide 
themselves with a breathing-machine, by means of 
which they can inhale the air from above the surface 
while they remain for a long time in the water. 
Nature has provided the elephant with something of 
this sort by giving him a long nose. If ever the 



659 a 

dpavres dvto hid rod vSaros rov fivKrrjpa, dv irore 
ttolcovtoli Bi' vypov TTjv nope'iav KaQdirep yap 

15 etTTOfxeVj \ivktt\p eortv Tj TTpofioOKlS to is i\i<f)aoLv. 
errel S* dhvvarov r)v elvai rov \xVKTr\pa rotovrov fir) 
pLaAaKov ovra pbrjhe KafiTTTeaOaL hwd/xevov (eveno- 
hi£e yap dv ra> pirjKeL Trpos to Xafielv rrjv 9vpa6ev 
Tpcxfrrjv, KaQduep tf>aul rd Kepara tols oTTLoOovofxois 

20 fiovolv Kal ydp eKeivovs vepLeaQal <f)aaiv vtto- 
ycopovvras iraXi pL7Tvyrjh6v) — vrrdp^avros ovv roiov- 
rov rod fjLVKrfjpos, rj <f>VGLS TTapa/caTa^p^ratj Ka9- 
direp ectoOev, ZttI irXeiova rdls avrols p.opLOis y dvrl 
rrjs Ttov TrpoaOttov Trohtov xP^' ia S- tovtovs ydp rd 
TToXvSaKrvXa Ttov rerpaTrohajv dvrl veipoov e^ovGiv, 

25 dXX ov piovov evex vTTOurduecos rov fidpovs' oi S' 
iXecfravres Ttov TroXvSaKTvXojv elal, Kal ovre St^a- 
Xov$ €)(ovglv ovre pLtovvx&s rovg rrohag- eirel Se to 
fxeyeOos ttoXv Kal to fidpos to rov oojparo?, Sta 
tovto jjlovov IpeLupLarog elui ydp lv > Ka ^ § t( * T W 
fipaSvTrjra Kal tt)v dtjivtav rrjs Kapufjetog ov XPV' 

GLflOL 1 TTpOS dXXo OvOiv. 

30 Aia piev ovv rrjv dvaTrvorjv I'vet pLVKTrjpa, KaSdirep 
Kal Ttov dXXcov eKaoTov Ttov i^ovrajv irXevpiova 
^(LcoVy hid he tt)v ev Tto vypto hiarpL^rjv Kal ttjv 
fipahvTrjTa tt)s eKeWev pLerafSoXfjs Svvdpievov IXIt- 
TeoBai Kal \iaKpov d(f>rjprjpevr)s he Trjs rcov Trohtov 

35 XPV G€0J ^> Ka * L V </>VGt>S> tuoTrep eiTTopiev, KaTaxpr)rai 
Kal TTpos TTjv drro Ttov Trohtov ywopLevrjv dv fior]6eiav 

TOVTO) Ttp pLOplw. 

659 b 01 8' opvtOeg Kal ol octets Kal Sua d'AA' evaifia 
1 XPV 01 ^ 01 Rackham : xpfow * vulg. 



elephant has to make his way through deep water, 
he will put his trunk up to the surface and breathe 
through it. This is possible, because, as I have said 
already, the trunk is really a nostril. Now it would 
have been impossible for the nostril to be put to all 
these uses if it had not been soft and able to bend ; 
for then by its very length it would have prevented 
the animal from getting its food, just as they say the 
horns of the " backward-grazing " oxen do, forcing 
them to walk backwards as they feed. a So the trunk 
is soft and pliable ; and in consequence Nature, as 
usual, takes advantage of this to make it discharge 
an extra function beside its original one : it has to 
serve instead of forefeet. Now in polydactylous 
quadrupeds the forefeet are there to serve as hands, 
not merely in order to support the weight of the 
animal ; but elephants (which must be included under 
this class of animals, because they have neither a 
solid hoof nor a cloven one) are so large and so heavy 
that their forefeet can serve only as supports ; and 
indeed they are no good for anything else because 
they move so slowly and are quite unsuited for 

So the elephant's nostril is there, in the first place, 
to enable him to breathe (as in all animals that have 
a lung) ; and also it is lengthened and able to coil 
itself round things because the elephant spends 
much of his time in the water and cannot quickly 
emerge upon land. And as his forefeet are not 
available for the normal function, Nature, as we 
said, presses the trunk into service to supply what 
should have been forthcoming from the feet. 

The Birds and Serpents and the quadrupeds which 

See above, on 648 a 16. This is from Herodotus, iv. 183. 

g2 195 


659 b 

/cat wotokgl 1 rwv rerpair6hwv } rovs fiev iropovs 
e)(ovai rwv fivKrrjpwv irpd rod crrofiaros, ware S' 
elneiv fJLVKrrjpas } el fir) Std to epyov 3 ovk e'xovat 
<f>avepws SirjpOpwfievovs' dAA' 17 y opvis wore 

5 firjOev dv etVetv e^et 2 ptvas. rovro Se crvfi^eprjKev, 
otl dvrl oiayovwv e^et ro KaXovfievov pvyxos. atria 
Se rovrwv r) <f>vois r) rwv 6pvL8wv ovvecrrrj Kvia 
rovrov rdv rporrov. hlrrovv yap eort /cat rrrepv- 
ytorov, coot* dvdyKrj fiiKpdv to fidpos e^et^ to tou 
avx^vos /cat to rrjs Ke<f>aXrjs, worrep /cat ro arrjOos 

10 arevov ottws fiev ovv fj xPV (Ji l JL0V ^pos re rr)v 
dXKTjv Kal Std ttjv rpo<f>rjv } oorwoes e'xovoi ro 
pvyxoSy orevdv he Std rrjv fiLKporrjra rrjs Ke<f)aXrj$. 
ev Se rw pvyx^i rovs rropovs exovcrt rrjs oocjtprjo'ews, 
fiVKrrjpas S' e^et^ dhvvarov, 

Yiepl Se rwv dXXcov £wwv rwv fir) dvauveovrwv 

15 elpr\rai irporepov hi r)v alrtav ovk e^oucrt fiv- 
Krrjpas, dXXd rd fiev Std rwv fipayxttov , rd Se Std 
tou avXov 3 rd S' evrofia Std tou VTro^wfiaros 
aloQdvovrai rwv 6ofiwv } Kal rrdvra rw avfi(f)vrw 
rrvevfiari rod owfiaros wrrep 3 ^/cat) 4 Kivelrai* rovro 
S* vrrapx^ <j>voei iraoi /cat ov BvpaBev eueloaKrov 
ear iv. 

20 'Ttto Se tous" fiVKrrjpas r) rwv ^etAcov eort envois 
rots exovoi rwv ivalfiwv ooovras. rots yap opvcot, 
KaOdrrep ei7T0jiev } Std rr)v rpo<f>r)v Kal rrjv dXKrjv ro 
pvyXOS oarwhes icrriv ovvrjKrai yap els ev avr 
ohovrwv Kal ^etAcui^ wcirep dv el res d<f>eXwv 

25 dvdpwTTOV rd X e ^V Ka ^ L <rvfi<f>vaas rovs dvwBev 

1 tpOTOKa Z, vulg. : ^a)OTOKa EPSUY. 
2 l^et S : ex €iv vu ^* 



like them are blooded and oviparous, have their 
nostril-passages in front of the mouth : but they have 
nothing which except for its function can be called 
nostrils — nothing distinctly articulated. A bird, at 
any rate, one might say has no nose at all. The 
reason for this is that its beak really replaces jaws. 
And this is because of the natural structure of birds. 
A bird is a winged biped ; hence its head and its neck 
must be light in weight, and its breast must be 
narrow ; and it has a beak, which (a) is made out of 
bony material, so that it will serve as a weapon as 
well as for the uptake of food, and (6) is narrow, owing 
to the small size of the head. It has the passages for 
smell in this beak, but it is impossible for it to have 
nostrils there. 

We have spoken already about the animals that do 
not breathe, and shown why they have no nostrils : 
some of them smell by means of the gills, some 
through a blow-hole ; while the insects smell through 
the middle part of the body. All of them smell, as 
all of them move, by means of the connate pneuma ° 
of their bodies, which is not introduced from without, 
but is present in all of them by nature. 

In all blooded animals that have teeth, the lips have Lip#. 
their place below the nostrils. (As stated already, 
birds have a bony beak for getting food and for de- 
fence ; and this is as it were teeth and lips run into 
one. The nature of the beak can be illustrated thus. 
Supposing, in a human being, that the lips were 
removed, and all the upper teeth were welded to- 

a Cf. De somno et vig. 455 b 34- ff. For a full account of 
TiVfjL(f>vrov UveOfia see G.A. (Loeb edn.), pp. 576 ff. 

* wtt€p SUZ 2 : woTTtp vulg. * <Kal> Peck. 



659 b ^ f 

ohovras x^P^S ^at KarwOev rrpoayayoi pcrjKos 

TTOLiqoaS dfl(f)Orepw9eV els <JT€VOV €17) ydp aV TOVTO 

rjhrj pvyxps opvtOwhes. rocs fiev ovv aXXois ^wocs 
irpos owrrjplav rwv ohovrwv r) rwv ^etAcuv <f>vais 
earl Kal -npos cpvXaKrjv, hionep ws eKelvwv fier- 

30 exovoi rod aKpifiws Kal kolXws r] rovvavrlov, ovtw 
Kal rod hir]p9pwu6ai tovto to (idpiov k'xovoiv' oi §' 
avOpcoTTOL fiaXaKa Kal aapKwhrj Kal hvvd[ieva X^P 1 '" 
£eo*#at, <f>vXaKrjs 9* eveKa rwv ohovrwv woirep /cat 
rd d'AAa, /cat fjiaXAov eVt Std to ev' Trpos ydp to 
XprjaBai rw Xoyw Kal ravra. wanep yap rr\v 

35 yXwrrav ovx djiotav rots aXXous eTroirjaev r) <f>vois, 
rrpos ipyaalas hvo Karaxprjaapievrj, Kaddnep 

660 a etVo/xev TTOieiv avrrjv e-nl ttoXXwv, rrjv piev yXwrrav 

rwv re xyfAwv zveKev Kal rod Xoyov, rd he ^etA^ 
rovrov 6* eveKev koX rrjs rwv oiovrwv tpvXaKrjs* 6 
jiev yap Xoyos 6 Std rrjs <f)wvrjs e« rcov ypapLjidrwv 
ovyKetrai, rrjs he yXwrrrjs [Jirj roiavrrjs ovarjs firjhe 

5 rwv x €L Xojv vypwv ovk dv fjv <f>6eyyea8ai rd rrXelora 
rwv ypafjbfidrwv rd fiev yap rrjs yXwrrrjs elol 
TTpoafioXaL, rd he avfi^oXal rwv xetAcuv. Trolas he 
ravra Kal rrooas Kal rlvas %X €L hiacpopds. Set 
TTwddveodai napd rwv jierpiKwv. 

'AvdyKrj S' rjv evQvs aKoXovOrjaai rovrwv rwv 

io [xoplwv eKarepov rrpos rrjv elprjp.evrjv xprjcrtv evepyd 
Kal roiavrrfv exovra rrjv <f>VGLV hid odpKiva. fia- 
XaKwrdrrj 8' r) crdpt; r) rwv dvdpwTTWV VTrrjpx^v. 
tovto he Sta. to alodrjTiKwraTOV etvac rwv £>wwv 
rrjv hid rrjs dtfirjs aiaOrjGLV. 


gether, and similarly all the bottom teeth, and then 
each set were extended in a forward direction, and 
made to taper : this would result in a beak such as 
birds have.) In all animals except man the lips are 
intended to preserve and to protect the teeth ; hence 
we find that the distinctness of formation in the lips 
is directly proportionate to the nicety and exactitude 
of formation in the teeth. In man the lips are soft 
and fleshy and can be separated. Their purpose is 
(as in other animals) to protect the teeth ; but — 
still more important — they subserve a good pur- 
pose, inasmuch as they are among the parts that 
make speech possible. This double function of the 
human lips, to facilitate speech as well as to protect 
the teeth, may be compared with that of the human 
tongue, which is unlike that of any other animal, and 
is used by Nature for two functions (a device of hers 
which we have often noted), (a) to perceive the 
various tastes, and (b) to be the means of speech. 
Now vocal speech consists of combinations of the 
various letters or sounds, some of which are produced 
by an impact of the tongue, others by closing the lips ; 
and if the lips were not supple, or if the tongue were 
other than it is, the greater part of these could not 
possibly be pronounced. For further particulars 
about the various differences between these sounds 
you must consult the authorities on Metre. 

It was necessary, however, from the start that each of 
these two parts should be adapted and well-fitted for 
their function as stated above ; therefore their nature 
had to be suitable thereto, and that is why they are 
made of flesh. Human flesh is the softest kind of flesh 
there is ; and this is because man s sense of touch is 
much more delicate than that of any other creature. 



660 a 

XVII. c Ytt6 Se rov ovpavov iv rw arofiart rj 
]5 yXwrra rots £wois earl, rots fJiev Tre^ois cr^eSov 


Trpos avra Kal Trpos rd Tre^a rwv £,wwv. 6 fiev ovv 
dvOpwrros aTToXeXvfJbevrjv re fidXtara rrjv yXwrrav 
Kal -rrXaretav Kal piaXaKwrdrrjv e'xei, 1 ottws Trpos 
djx<f)orepas fj ras epyaolas ^p^cri/Lio?, Trpos re rrjv 

20 rwv yy\xwv aloOrjciLV (o yap dvdpwrros evaiodrjro- 
raros rwv d'XXwv £wwv, Kal rj fiaXaKTj yXwrra 
(^alaOrjrLKwrdrri) 2 - aTrrLKwrdrr] yap, rj Se yevots d<f>rj 
rLs ioriv) y Kal Trpos rrjv rwv ypafifidrwv SidpOpwoLV 
Kal Trpos rov Xoyov rj fxaXaKrj Kal 7rAaTeta XPV~ 
Gipios' orvareXXecv yap teal TrpofidXXeiv TravroSaTrrj 

25 roiavrrj ovaa Kal dTroXeXvfJLevrj pidXiar av hvvairo. 
SrjXol 8' ogols [^rj Xlav aTroXeXvrai' ipeXXt^ovrai 
yap Kal rpavXi^ovoij rovro 8' iarlv k'vSeta rwv 
ypa t ufJbdrwv . 

"Et> re rw rrXarelav elvai Kal ro orevr\v ioriv 

iv yap rw fieydXw Kal ro jiiKpov, iv Se rw fiiKpw 

ro fieya ovk eoriv. Sio Kal rwv opvldwv ol jidXiara 

so cf>6eyy6fi€V0L ypdfifiara rrXarvyXwrrorepoi rwv aX- 

Xwv elalv. ra 8' evaifxa Kal ^woroKa rwv rerpa- 

ttoSwv fipa)(€iav rrjs <f>wvrjs e^ei hidpdpwaw 

GKXrjpdv re yap Kal ovk dTroXeXviievrjv e^owi 

Kal Traxetav rrjv yXwrrav. rwv 8' opvldwv evioi 

TroXv(j)wvoL, Kal TrXarvrepav ol yapj^wwypi eypvoiv. 

35 TToXv<f)WVOL 8' ol puKporepoi. Kal xpwvrat rfj 

yXwrrrj Kal Trpos ep\it]velav aXkr\Xois rrdvres [lev, 

660 b erepoL Se rwv erepwv fi&XXov, war iTT ivlwv Kal 

1 Kal paX. Ix €t P os t t€ vulg. ; transposui. 
2 aiodrjTiKCOTaTT) Supplevi. 



XVII. Under the vaulted roof of the mouth is Tongue, 
placed the tongue, and it is practically the same in 
all land-animals ; but there are variations in the other 
groups, whose tongues are as a whole different from 
those of land-animals and also different among them- 
selves. The human tongue is the freest, the broadest, 
and the softest of all : this is to enable it to fulfil 
both its functions. On the one hand, it has to per- 
ceive all the various tastes, for man has the most 
delicate senses of all the animals, and a soft tongue 
is the most sensitive, because it is the most re- 
sponsive to touch, and taste is a sort of touch. It 
has, also, to articulate the various sounds and to 
produce speech, and for this a tongue which is soft 
and broad is admirably suited, because it can roll 
back and dart forward in all directions ; and herein 
too its freedom and looseness assists it. This is 
shown by the case of those whose tongues are slightly 
tied : their speech is indistinct and lisping, which 
is due to the fact that they cannot produce all the 

A tongue which is broad can also become narrow, 
on the principle that the great includes the small, 
but not vice versa. That is why the clearest 
talkers, even among birds, are those which have 
the broadest tongues. On the other hand, the 
blooded viviparous quadrupeds have a limited vocal 
articulation ; it is because their tongues are hard 
and thick and not sufficiently loose. Some birds — 
the smaller sorts — have a large variety of notes. 
The crook-taloned birds have fairly broad tongues. 
All birds use their tongues as a means of communica- 
tion with other birds, and some to a very consider- 
able extent, so much so that it is probable that in 



fidOrjGLV elvai Sok€lv Trap" dXXrjXwv ecprjTai Se 7rept 
avTwv iv tolls laroplais tols irepl twv t,wwv. 

Twv Se rre^cov Kal wotokwv Kal lvat\xwv Trpos 
fjLev rrjv rrjs cjxjovrjs ipyaalav d'xp'qGTOV ra 77oAAd 
5 ttjv yXtorrav e^et kol TTpoGoehepLeviqv Kal GKXrjpdv, 

TTpOS 0€ TTJV TWV yy[i.GsV y€VGLV OL T 0(j)€LS KOL ol 

aavpoi pLCLKpav Kal oiKpoav ex ov<7iV > °* o<f>€t,s 


oiKpoav ok Kal to aKpov Xctttov koll TpLxwBes Sia 
tt)v Xi)(y€iav rrjs <j)VG€ws' $i7rXrjv yap ttjv rjSovrjV 

10 /crarat twv x v l JL< ^ )V > oouirzp 0L7rXr\v eypvTa ttjv Trjs 
yevGews aiudr\Giv. 

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OLaTptfieiv eKxvfJLL^ovras' irapepsnl'TTTOL yap dv to 

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° See Hist. An. 504 b 1, 536 a 90 ff„ 597 b 26, 608 a 17, 



some cases information is actually conveyed from one 
bird to another. I have spoken of these in the 
Researches upon Animals. 0, 

The tongue is useless for the purpose of speech in 
most of the oviparous and blooded land-animals be- 
cause it is fastened down and is hard ; but it is very 
useful for the purpose of taste, e.g. in the serpents and 
lizards, which have long, forked tongues. Serpents' 
tongues are very long, but can be rolled into a small 
compass and then extended to a great distance ; they 
are also forked, and the tips of them are fine and hairy, 
owing to their having such inordinate appetites ; by 
this means the serpents get a double pleasure out 
of what they taste, owing to their possessing as it 
were a double organ for this sense. 

Even some of the bloodless animals have an organ 
for perceiving tastes ; and of course all the blooded 
animals have one, including those which most people 
would say had not, e.g., certain of the fishes, which 
have a paltry sort of tongue, very like what the river- 
crocodiles have. Most of these creatures look as if 
they had no tongue, and there is good reason for this. 

(1) All animals of this sort have spinous mouths ; 

(2) the time which water-animals have for perceiv- 
ing tastes is short ; hence, since the use of this 
sense is short, so is the articulation of its organ. 
The reason why their food passes very quickly into 
the stomach is because they cannot spend much time 
sucking out its juices, otherwise the water would get 
in as well. So unless you pull the mouth well open, 
you will not be able to see that the tongue is a sepa- 
rate projection. The inside of the mouth is spinous, 
because it is formed by the juxtaposition of the gills 
which are of a spinous nature. 



Tot? Se KpoKoSeiXois ovfifidXAeral ri rrpos rrjv 
rod fiopiov rovrov dvarrrjpiav koX to rrjv aiayova 


rfj Karw ovficfrvrjs, ol 8' exovotv woirep dvdrraXiv 
rrjv dvw koltcd* rots yap dXXots rj dvw dKivrjros. 

30 7rpos l±tv ovv rfj dvw ovk k'xovui rrjv yXwrrav, on 
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en 8k kcll avfipefirjKev avrw rre^w ovn tfiv ixdvwv 
fiioVy ware koX hid rovro dvayKalov ahidpOpwrov 
avrov k'xeiv rovro to fiopiov. 

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rots Be TrpooTre^vKoSi oaois firjSkv epyov virdpx^ 

1 [tt}s Tpo(f>i}$ x^P tv l praecedentium interpretationem seclusi, 
cetera correxi: rrjs eV rot? xu/toZs ecrr i v V oloBfiots {els atodrjoiv 

X) TO fJL€V {fl€V TO EYZ) yAcOTTO€lSe? {*X €t ° m * ^) pOpWV 

\nlg. 2 vavrl 7i : 7ra.vrr] vulg. 



Among the factors which contribute to the de- 
formity of the crocodile s tongue is the immobility 
of its lower jaw, to which the tongue is naturally 
joined. We must remember, however, that the 
crocodile's jaws are topsy-turvy ; the bottom one is 
on top and the top one below ; this is clearly so, 
because in other animals the top jaw is the immovable 
one. The tongue is not fixed to the upper jaw (as 
one might expect it to be) because it would get in 
the way of the food as it entered the mouth, but to 
the lower one, which is really the upper one in the 
wrong place. Furthermore, although the crocodile 
is a land-animal, his manner of life is that of a fish, 
and this is another reason why he must have a tongue 
that is not distinctly articulated. 

Many fish, however, have a fleshy roof to their 
mouths. In some of the fresh-water fish — e.g. 
those known as Cyprinoi — it is very fleshy and soft, 
so that casual observers think it is a tongue. In 
fish, however, for the reason already given, the 
tongue, though articulated, is not distinctly so ; yet, 
inasmuch as the power also of perceiving tastes 
resides in the tongue-like organ, though not in the 
whole of it equally but chiefly in the tip, therefore on 
this account in fish the tip only is separate from the 

Now all animals are able to perceive the pleasant 
taste which is derived from food, and so they have a 
desire for food, because desire aims at getting that 
which is pleasant. The part, however, by which this 
perception or sensation of the food takes place, is 
not identical in all of them, for some have a tongue 
which moves freely and loosely, others (which have no 
vocal functions) have a tongue that is fastened down. 



la t 
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80 irdvTwv cgtIv otavrrep eLTTOfiev. 

° Under this name Aristotle probably includes several 
species of Purpura and Murex. Tyrian purple (6, 6' dibrom- 



Some again have a hard tongue ; others a soft or 
fleshy one. So we find that even the Crustacea — e.g. 
the Crayfish and such — have a tongue-like object 
inside the mouth, and so have the Cephalopods — e.g. 
the Sepias and the Octopuses. Of the Insects, some 
have this organ inside the mouth (e.g. the Ants), 
and so have many of the Tcstacea. Others have it 
outside, as though it were a sting, in which case it is 
spongy and hollow, and so they can use it both for 
tasting and for drawing up their food. Clear ex- 
amples of this are flies and bees and all such creatures, 
and also some of the Testacea. In the Purpurae, a for 
instance, this " tongue " has such strength that they 
can actually bore through the shells of shellfish with 
it, including those of the spiral snails which are used 
as baits for them. Also, there are among the gad- 
flies and cattle-flies creatures that can pierce through 
the skin of the human body, and some can actually 
puncture animal hides as well. Tongues of this sort, 
we may say, are on a par with the elephant's nose ; 
in their tongue these creatures have a useful sting 
just as the elephant has a handy implement in his 

In all other animals the tongue conforms to the 
description we have given. 

indigo) is obtained from Murex brandaris. For the boring 
powers of these creatures' tongues see the reference for 
Purpura lapillus given by Ogle (Forbes and Hanley, Brit. 
Mollusca, iii. 385). 



'E^o^evov he tqjv elprjfievwv rj rtov oSovtwv 

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twv aXXwv l,wwv t Sua firj 7rdvTas ex ov<JLV o^eis 
— [idXiGTa Se Kal tovtovs toiovtovs Kal togov- 




The subject which follows naturally after our previous Teeth, 
remarks is that of the Teeth. We shall also speak 
about the Mouth, for this is bounded by the teeth 
and is really formed by them. 

In the lower animals teeth have one common 
function, namely, mastication ; but they have addi- 
tional functions in different groups of animals. In 
some they are present to serve as weapons, offensive 
and defensive, for there are animals which have 
them both for offenee and defenee (e.g. the wild 
carnivora) ; others (including many animals both 
wild and domesticated) have them for purposes of 

Human teeth too are admirably adapted for the 
common purpose that all teeth subserve : the front 
ones are sharp, to bite up the food ; the molars 
are broad and flat, to grind it small ; and on the 
border between the two are the dog-teeth whose 
nature is intermediate between the two : and just as 
a mean shares the nature of both its extremes, so 
the dog-teeth are broad in one part and sharp in 
another. Thus the provision is similar to that of 
the other animals, except those whose teeth are 
all sharp ; but in man even these sharp teeth, in 
respect of character and number, are adapted 
chiefly for the purposes of speech, since the 



15 yiveGiv twv ypapL^idrwv oi TrpduQioi twv oBovrwv 
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rep ndXicrra, otov Kevrpov, TrXrjKrpov, Kepara, 
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dppev lo-^vporepov /cat OvpLiKwrepov, rd jxev \iova 
rd Be fJL&XAov e%ei rd roiavra rtov jxopiwv. oaa 

85 jxev ydp dvayKalov /cat rots drjXeaiv eyeiv, otov rd 


Be irpds pLi]Sev rwv dvayKaiwv, ovk e'xovaiv, /cat 
See note on 644 a 17. 



front teeth contribute a great deal to the formation 
of the sounds. 

As we have said, the teeth of some of the animals 
have one function only, to break up the food. Of 
those animals whose teeth serve also as a defence 
and as weapons, some (like the Swine) have tusks, 
some have sharp interlocking teeth, and are called 
" saw-toothed " as a result. The strength of these 
latter animals lies in their teeth, and sharpness is 
the means of securing this ; so the teeth which are 
serviceable as weapons are arranged to fit in side by- 
side when the jaws are closed to prevent them from 
rubbing against each other and becoming blunt. No 
animal has saw-teeth as well as tusks ; for Nature 
never does anything without purpose or makes any- 
thing superfluously. These teeth are used in self- 
defence by biting ; tusks by striking. This explains 
why sows bite : they have no tusks. 

(At this point we should make a generalization, "The more 
which will help us both in our study of the foregoing ^ ^ he 
cases and of many that are to follow. Nature allots 
defensive and offensive organs only to those creatures 
which can make use of them, or allots them "in a 
greater degree," and " in the greatest degree " to 
the animal which can use them to the greatest ex- 
tent. This applies to stings, spurs, horns, tusks, and 
the rest. Example : Males are stronger than females 
and more spirited ; hence sometimes the male of a 
species has one of these parts and the female has 
none, sometimes the male has it "in a greater degree." 
Parts which are necessary for the female as well as 
for the male, as for instance those needed for feed- 
ing, are of course present though " in a less degree " ; 
but those which serve no necessary end are not 



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tovtwv eivai, 

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20 kolvols irdvTWV fjLoptoLS els TToXXd twv lolwv Kara- 
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errepwVy eTi he to dvaTrveiv ou udvTWv kolvov. rj he 
1 sic P : dialpeoiv. ttoXlv kclI vulg. 

a Probably the parrot-fish. Cf. 675 a 3. 



present. Thus, stags have horns, does have not. 
Thus, too, cows' horns are different from bulls' horns, 
and ewes' from rams'. In many species the males 
have spurs while the females have not. And so with 
the other such parts.) 

All fishes are saw-toothed except one species, 
the Scarus. Many of them have teeth on their 
tongues and in the roof of the mouth. This is 
because as they live in the water they cannot help 
letting some of it in as they take in their food, and 
they have to get it out again as quickly as possible. 
If they failed to do so, and spent time grinding the 
food small, the water would run down into their gut. 
So all their teeth are sharp and intended only for cut- 
ting up the food. Further, they are numerous and 
placed all over the mouth ; so b}* reason of their 
multitude they can reduce the food into tiny pieces, 
and this takes the place of the grinding process. 
They are also curved ; this is because practically the 
whole of a fish's offensive force is concentrated in 
its teeth. 

The mouth, too, is present in animals on purpose Mouth, 
to fulfil these same offices, but it has also a further 
purpose, at any rate in those animals which breathe 
and are cooled from without — namely, to effect re- 
spiration. As we said earlier, Nature will often quite 
spontaneously take some part that is common to all 
animals and press it into service for some specialized 
purpose. Thus, the mouth is common to all animals, 
and its normal and universal function has to do with 
food : but sometimes it has an extra function, peculiar 
to some species only : in some it is a weapon, in others 
a means of speech ; or more generally, though not 
universally, it serves for respiration. Nature has 



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brought all these functions together under one part, 
whose formation she varies in the different species to 
suit its various duties. That is why the animals 
which use their mouths for feeding, respiration and 
speaking have rather narrow mouths, while those 
that use them for self-defence have wide and gaping 
mouths. All the saw-toothed creatures have these 
wide mouths, for their method of attack is biting, and 
therefore they find it an advantage to have a mouth 
that will open wide ; and the wider it opens the 
greater the space the bite will enclose, and the 
greater the number of teeth brought into action. 
Biting and carnivorous fishes have mouths of this 
sort ; in the non-carnivorous ones it is on a tapering 
snout, and this suits their habits, whereas a gaping 
mouth would be useless. 

In birds, the mouth appears in the form of a beak, Beak, 
which serves them instead of lips and teeth. Various 
sorts of beak are found, to suit the various uses in- 
cluding defensive purposes to which it is put. All 
of the birds known as crook-taloned have a curved 
beak, because they feed on flesh and take no vegetable 
food : a beak of this form is useful to them in master- 
ing their prey, as being more adapted for the exertion 
of force. Their beak, then, is one weapon of offence, 
and their claws are another ; that is why their claws 
are exceptionally curved. Every bird has a beak 
which is serviceable for its particular mode of life. 
The woodpeckers, for instance, have a strong, hard 
beak ; so have crows, and other birds closely related 
to them ; small birds, on the other hand, have 
a finely constructed beak, for picking up seeds and 
catching minute animals. Birds that feed on herb- 
age and that live by marshes (e.g. swimmers and 



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rpoTTOV -^pr]Gi\iov e^€t to pvyyos, ra Se irXarvpvyx^ 
avrwv iariv roiovrw yap ovn pqSttus hvvarai 
opvacreiv, warrep Kal rwv rerpaTroSwv ro rrj$ uos"* 
Kal yap avrrj pit>o<f>dyos . eVt S' e^oucri /cat Ta 

15 pi^cxfidya rwv opviwv Kal rwv 6pLoiof3lwv kvia ra 
aKpa rod pvyxovs Ke^apay^eVa^ 7ror}cf)dyoi$ yap 
rovroig ovoi Troiet pahlwg. 

Tlepl fiev ovv rwv dXXwv ptopCwv rwv ev rfj 
K€<j>a\fj cx^ov eLprjrai, rwv S' dvOpwnwv KaXelrai 
to fiera^v rrjg K€(f>aXrjs Kal rov atr^eVo? TTpocwnov, 

20 aTTO rfjg npd^ews avrrjg ovopLaadiv, ws eoiKtv Sia 
yap to plovov opdov elvat rwv t,wwv povov irpoo- 
wdev o7TW7T€ Kal rrjv (pwvrjv els to Ttpoow Sia- 


II. Uepl Se K€pdrajv XeKriov Kal yap ravra 

7T€(f)VK€ rOLS ^OVULV ^ V T V K ^4>°^Xfl' ^X €l ^ OTjStV 

25 pir] t,q)oroKov. Kad* opoLorrjra Se Kal pcraj>opdv 
Xeyerat Kal irepwv nvwv K€para- dXX ovSevt, 
avrwv ro epyov rod Keparos virdpx^* fiorjQeias 
yap Kal dXKrjg X^P lv ^X 0V<Jl T( * ^wotokgl, o rwv 
aXXwv rwv Xzyopievwv e^etv Kepag ovSevl wpi- 
f34f3r}Kev ovhev yap XPV TCLL ro ^S Kepacriv ovr 

30 dpvvopevov ovre irpos to KpareXv, dnep laxvo$ 
icrlv epya. b'aa pLev ovv 7ioAucr^t§7] rwv l^wwv, 
ovhev e^ei Kepas. rovrov S' atriov on ro pcev 
Kepas fiorjBelas alriov eon, rois Se ttoXvox^€glv 
VTrdpxovaiv erepai jSorj^etar hebwKe yap rj <f>voi$ 
rois pLev ovvx&S rots S' dSovTa? piax^riKovs, rots 

Under this heading all the Mammalia known to Aristotle 


web-footed birds) have a beak adapted for their 
mode of life, a special instance of which is the broad 
beak, which enables them to dig for roots easily, just 
as the broad snout of the pig enables it to dig — an 
example of a root-eating quadruped. These root- 
eating birds and other birds of similar habits some- 
times have sharp points at the end of the beak. This 
enables them to deal easily with the herbaceous food 
which they take. 

We have now, I think, spoken of practically all 
the parts that have their place in the head ; but 
in man, the portion of the body between the head 
and the neck is called the Prosopo?i (Face), a name 
derived, no doubt, from the function it performs. 
Man, the only animal that stands upright, is the 
only one that looks straight before him (prosdtke?i 
opope) or sends forth his voice straight before him 
(proso, opa). 

II. We still have to speak of Horns : these also, Horns, 
when present, grow out of the head. Horns are 
found only in the Vivipara ; though some other 
creatures have what are called horns, owing to their 
resemblance to real horns. None of these so-called 
horns, however, performs the function proper to horns. 
The reason why the Vivipara have horns is for the 
sake of self-defence and attack, and this is not true 
of any of these other creatures, since none of them 
uses its " horns " for such feats of strength either 
defensively or offensively. The polydactylous ani- 
mals, a moreover, have no horns, because they possess 
other means of defence. Nature has given them claws 
or teeth to fight with, or some other part capable of 

are included, except ruminants, solid-hoofed animals, and 



662 b 

35 §' d'AAo rt fxopiov ikclvov dpLvvew. rwv Se hi\6Xwv 

663 a ra pev 7ToAAa Kepara e^et rrpos dXKrjv, /cat rwv 

fibovvxcDV IVta, Ta Se /cat irpos fiorjOeiav, ogols 1 firj 
SeSwKev r) cf>v(Jis d'XArjv olAktjv TTpog owrrjpiav, olov 
raxvrrjra ocofiaros, KaOdrrep rols ittttols pefiorjdrj- 
K€v } Tj peyedos, woirep rat? KapL-qXois' /cat yap 
5 pueyedovs virepfioXr) rrjv diro rwv aAAa>j> £wwv 
cf)6opdv iKavrj KwXveiv, oTrep ovp,fiefir)K€ rats' KapLrj- 
XotSt en Se pidXXov rols eAe'</>acrtv. rd Se ^auAt- 
dSovra, woirep /cat ro rwv vwv yevos, St^aAov (pv). 2 

"OoOlS S' dxpT]OTOS 7T€<f)VKeV 7} TWV Kepdrwv 

e^ox^j, tovtois TrpooreOeiKev erepav fioiqQeiav rj 
10 <f)V<JLS } olov rats* /xev eXd^ois ra^o? (to yap /Lte- 
yeOos avrwv /cat to tto Ava^tSe? jLtaAAoy fiXdirrei rj 
uxfieXel), /cat fiovfidXois Se /cat Sop/caat (wpds evta 
/xev yap dvOuordpieva rols /cepaatv dpivvovrai, rd oe 
OrjpiwSrj /cat jaa^tjaa aTTocfrevyovoi) , rols Se fiovdoois 
(/cat yap Tourots" yapifjd rd Kepara ire^vKe Trpos 
15 aAA^Aa) tt)v row rreptrrwpiaros dcfreoiv rovrw ydp 
dpivver ai <f>oj3r)0evra' /cat ravrrj Se ttJ irpoevei Sta- 
ow^erai erepa. dp.a S' t/cavas" /cat TrAetof? fio-qBeLas 
ov oeSwKev r) envois rols avrolg. 

"EaTt Se rd irXelora rwv K€parocj>6pa>v St^aAa, 
Ae'yeTat Se /cat pwvvxov, ov koXovgiv 'Ivolkov ovov. 
20 Ta pLev ovv irXelora, KaOdirep /cat rd uwpia 
oLfjprjraL rwv l^wwv ots iroielrai rrjv KLvrjOLV, Se£tov 
/cat dptorepov, /cat Kepara Svo TrecfyvKev exeiv Sta 

1 post oaois vulg. : del. Piatt, Thurot. 
2 <o»> Ogle. 

• Cf. above, on 648 a 16. 
6 The European bison. 

e This is probably the Indian Rhinoceros. This account 


rendering adequate defence. Most of the cloven- 
hoofed animals, and some of the solid-hoofed, have 
horns, as weapons of offence ; some have horns for 
self-defence, as those animals which have not been 
given means of safety and self-defence of a different 
order — the speed, for instance, which Nature has 
given to horses, or the enormous size which camels 
have (and elephants even more), which is sufficient 
to prevent them from being destroyed by other 
animals. Some, however, have tusks, for instance 
swine, although they are cloven-hoofed. 

In some animals the horns are a useless appendage, 
and to these Nature has given an additional means 
of defence. Deer have been given speed (because 
the size of their horns and the numerous branches 
are more of a nuisance to them than a help). So 
have the antelopes and the gazelles, which, although 
they withstand some attackers and defend them- 
selves with their horns, run away from really fierce 
fighters. The Bonasus, b whose horns curve inwards 
to meet each other, protects itself when frightened 
by the discharge of its excrement. There are other 
animals that protect themselves in the same way. 
Nature, however, has not given more than one 
adequate means of protection to any one animal. 

Most of the horned animals are cloven-hoofed, 
though there is said to be one that is solid-hoofed, 
the Indian Ass, c as it is called. 

The great majority of horned animals have two 
horns, just as, in respect of the parts by which 
its movement is effected, the body is divided 
into two — the right and the left. And the 

of it comes from the Indica of Ktesias of Knidos, quoted in 
Photius's Bibliotheca, lxxii. pp. 48 b 19 (Bekker) foil. 

H 219 


663 a 

tt)v avrrjv alrtav 1 ' eon 8e Kal fjLovoK€para t oiov o 

T Opv£ KOLL 6 'IvOlKOS KaXoV[A€VOS 6V0S*. €OTl 8* O 

fJLev opv£ Si^aAov, 6 8* ovos fjubvvxov. ex €l ^ T( * 
25 {lovoKepara to Kepas iv rw fiioLp rrjs KtLpaXrjs' 
ovtlo yap eKarepov tlov pLtpwv pLaXiOT dv e^ot 
Ktpas €v to yap p.eoov ofiotcos kolvov dficpoTepLov 
tlov loyaTiov. evXoycos 8' aV So^eie fiovoKepLov 
elvai to fiwvvxov tov oixdXov fiaXXov ottXtj ydp 
Kal Xl^l T V P a VT"f)v e^ei KepaTL cbvoiv, waf a/xa 
so Kal rot? avTols r) o^iats* yiverat tlov ottXlov Kal 
tlov KepdTOJV. €tl 8* r) cr^'ats* Kal to oix&Xov /caT* 
eXXeii/jcv Trjs cpvaews ioTiv, lout evXoycos Tot? 
picovvxois iv rats' oTrAats 1 Soucra ti^v v7T€pox^)v 
rj <f>vocs avLoOev dchecXe Kal fjiovoKeptov iTrotrjuev. 
J 0p6(Zs 0€ Kal to iirl Tijg K€(f>aXrjs Troirjoai ttjv 
35 tlov KepaTtov Lpvocv, dXXd firj Kaddirep 6 KIglottov 
Mai/xos 1 ScafxificpeTat tov ravpov otl ovk iirl tois 
663 b djfioLs ix ec to, KepaTa y 66ev ras" TrXrjyds eVotetT* 
dv loxvpOTaTas , aAA* erri tol? doOevearaTov fiepovs 
tt)s KecpaXijs. ov yap 6£v fiXeTTLOv 6 MtD/.to? ravr 
€7T€TLfjLrjO€v. Looirep yap Kal el eTepLodi TTOV TOV 
5 otbjiaTos KepaTa irreL^VKti, fidpos dv irapeix^ dX- 
Xlos ovhkv ovTa ^p^cri/xa K ^ v i^dSia tcov epycov 


yap i-iovov xPV okottziv irodev ta^uporepai ai nXr)- 
yal, dXXd Kal iroOev rroppcoTepai' loot irrel ^€tpa? 
p.€v ovk €xovolv } irrl oe tlov ttoolov dovvaTov > iv 8e 

1 avTTjV alriav Peck : atrial' ravrrjv vulg. 
° See Babrius, Myth. Aesop. lix. 8-10. 



reason in both cases is the same. There are, how- 
ever, some animals that have one horn only, e.g. 
the Oryx (whose hoof is cloven) and the " Indian 
Ass " (whose hoof is solid). These creatures have 
their horn in the middle of the head : this is the 
nearest approximation to letting each side have its 
own horn, because the middle is common equally to 
both extremes. Now it is quite reasonable that the 
one horn should go with the solid hoof rather than 
with the cloven hoof, because hoof is identical in 
nature with horn, and we should expect to find 
divided hoofs and divided horns together in the same 
animal. Again, division of the hoof is really due to 
deficiency of material, so it is reasonable that as 
Nature has used more material in the hoofs of the 
solid-hoofed animals, she has taken something away 
from the upper parts and made one horn only. 

Again, Nature acted aright in placing the horns 
on the head. Momus in Aesop's fable is quite 
wrong when he finds fault with the bull for having 
his horns on the head, which is the weakest part of 
all, instead of on the shoulders, which, he says, 
would have enabled them to deliver the strongest 
possible blow. Such a criticism shows Momus 's 
lack of perspicacity. If the horns had been placed 
on the shoulders, as indeed on any other part of the 
body, they would have been a dead weight, and 
would have been no assistance but rather a hindrance 
to many of the animal's activities. And besides, 
strength of stroke is not the only point to be con- 
sidered : width of range is equally important. 
Where could the horns have been placed to secure 
this ? It would have been impossible to have them 
on the feet ; knees with horns on them would have 



rot? yovaoiv ovra rrjv KapupLV eKwXvev av, aray- 
10 kcuov cooirep vvv exovGiv, eul rrjs Ke(f)aXrjs e)(€iv. 

dfia Se Kal trpos rag dXXas Kivrjueis tov GCJjxaTOS 

avefXTToSiura nec^VKev ovrco fidXiara. 
"Eoti ra Kepara ol oXov orepea tols eXd<j)OLS 

fiovois, Kal dirofidXXeL [jlovov, eveKev jxev w<j>eXeLa$ 

Kov^L^ofxevov, i£ dvdyKTjs Se Sice to fidpos. rwv 8' 
is dXXa>v ra Kepara fxexpi tlvos KolXa, ra 8' a/cpa 

arepea 8ta to npos ras 7rXrjyds tovt elvai XPV" 

Gifjiov. ottcos 8e fJLTjSk to KolXov aG0eves fj o 1 

7T€<f)VK€V €K TOV SepfiaTOS, iv TOVTO) 2 evrjpjXOGTaL 

{to) 3 GTepeov €K twv oGTcbv ovTW yap Kal TCC 
KepaTa k'ypvTa irpos dXKrjv T€ xP r l <JL t Ji( ^ TaT * 

20 Kat TTpos tov dXXov fitov avo^XoraTa. 

TtVo? fiev ovv eveKev r) tqjv KepaTtov (f>VGL$, 
etpryraiy Kal Std tlv avrlav Ta jxev e'xovoL rocavra 
ra 8' ovk e'xovoLV 

II ws 8e Trjs dvayKalas <j>vaea>s exovorjs tols 
virdpxovoiv e£ dvdyKTjs rj Kara tov Xoyov </)vgls 
eveKa tov /cara/v-e^p^Tou , Xeyajfiev. 

26 UpwTOV fxev ovv to GtofiaTtoSes Kal yewBes rrXelov 
virdpx^ tols jxei^oGL to)v c^cpajv, KepaTO<f)6pov Be 
fjiiKpov rrdpLirav ovSev top.ev' eXdx^TOV yap eon tcov 
yvajpL^ofievcov SopKas* Set oe ttjv <f>VGLV dewpelv 
els Ta 77oAAa ^Xe7TOvra' rj yap ev tlo iravTl rj ibs eul 
to 7toXv to Kara <1>vglv Igtlv. to 8* OGTwSes ev 

1 o Peek* cf. Hist. An. 500 a 8: ov vulg., om. EPY: od 
suprascr. Z (v. p. 46). 2 tovtcd Peck : rovrco 8* vulg. 

3 <ro> Peck : cf. Hist. An. 500 a 9. 

4 earl Piatt : etvat vulg. : €it] av Thurot. 

* For the contrast between "necessary nature" and 


been unable to bend ; and the bull has no hands ; so 
they had to be where they are — on the head. And 
being there, they offer the least possible hindrance 
to the movements of the body in general. 

Deer alone have horns that are solid throughout ; 
and deer alone shed their horns : this is done (a) on 
purpose to get the advantage of the extra lightness, 
(b) of necessity, owing to the weight of the horns. 
In other animals the horns are hollow up to a certain 
distance, but the tips are solid because solid tips are 
an advantage when striking. And to prevent undue 
weakness even in the hollow part, which grows out 
from the skin, the solid piece which is fitted into it 
comes up from the bones. In this way the horns 
are rendered most serviceable for offensive pur- 
poses and least hampering during the rest of the 

This completes our statement of the purpose for 
which horns exist and the reason why some animals 
have them and some have not. 

We must now describe the character of that 
" necessary nature," owing to which certain things 
are present of ?iecessiiy, things which have been 
used by " rational nature " to subserve a " purpose." a 

To begin with, then : the larger the animal, the 
greater the quantity of corporeal or earthy matter 
there is in it. We know no really small horned 
animal — the smallest known one is the gazelle. (To 
study Nature we have to consider the majority of 
cases, for it is either in what is universal or what 
happens in the majority of cases that Nature's 
ways are to be found. Now all the bone in animals' 

" rational nature" see above 640 b 8-29, 641 a 25 ff., 642 a 
1 ff., and cf. G.A. (Loeb edn.), Introd. § 14. 



663 b f 

so Tot? crcofjiaoi rcov £cpcov yecoSes vnapyei* Sto /cat 

7rAetarov eV rot? pteylorots cos errl to 770A?) ^SAe- 
tpavra$ eliretv. t^v yow rotovrov trcofiaros rreptr- 

TO> jJLaTLKrjV V7T€pfioArjV iv TOL$ fiel^OGt TO)V £tpCOV 
V7TCLp)(OVOaV 6776 fiorjOetaV KCLL TO GVfJL(f>ipOV KOLTCL- 

XpfjraL rj (f>vGLSj KCLL rrjv peovaav i£ dvdyKrjs els rov 

a77€V€t/Z€, TOLS 8* els Kepara. OiO rcOV KepCLTO- 

(j)6pa>v ovSev eortv dfJt<f>co8ov dvco yap ovk e^ei rovs 

664 a TTpoadiovs dSovras' dcfyeXovaa yap evrevBev rj <f>vots 

rots Kepaot 7TpoaeBrjKe y Kai r] StSoptevT] rpo(f>r) els 
rovs oSovrag rovrovs els rrjv rtov Kepdrcov av^rjatv 
avaXtoKerat. rod Se rds OrjXetas eXdtf>ovs Kepara 

jlkv {17] €X€LV, TTCpl Se TOVS oSoVTa? OflOtCOS TOL£ 

5 dppeatv, atrtov rd rrjv avrrjv elvat (f>vatv dpttfrotv 
Kal Keparo(f>dpov, dcfyfjp-qrai Se rd Kepara rats 
BrjXetats Std to xPV (JL l JLa l 1 ^ l^V ewai Ltrjhe rots 
dppeatv, fiXdnreoQat 8' rjaaov Sid rrjv lo^vv. 

Ttbv S' dXXcov ^cpcov oaois fir) els Kepara diro- 
Kptverat rd rotovrov p.dptov rod acoptaros, evtots 
10 ptev rcov oSovtoj^ avrtov enrjv^ae rd pteyeBos Kotvfj 
irdvrajVj evtots Se ^auAidSovTas 1 toairep Kepara eV 
rcov yvdOcov euovqaev. 

Ile/n fiev ovv rcov ev rr\ KetfraXfj pop ttov ravrrj 

III. 'lVo Se rrjv Ke^aXrjv 6 au^r 7re<f)VKcos eon 
rots e'xovatv av^eva rcov ^cpcov. ov yap irdvra 
15 rovro rd ptdptov e%et, dAAd ptdva rd e^ovra cov 

° i.e. constituent substance. See on 648 a 2. 



bodies consists of earthy matter ; so if we consider 
the majority of cases, we can say that there is most 
earthy matter in the biggest animals.) At any rate, 
in the larger animals there is present a surplus of 
this corporeal or earthy matter, produced as a 
residue, and this Nature makes use of and turns to 
advantage to provide them with means of defence. 
That portion of it which by necessity courses upwards 
she allots to form teeth and tusks in some animals, 
and to form horns in others. And we can see from 
this why no horned animal has incisor teeth in both 
jaws, but only in the bottom jaw. Nature has 
taken away from the teeth to add to the horns ; 
so that the nourishment which would normally be 
supplied to the upper teeth is here used to grow the 
horns. Why is it, then, that female deer, although 
they have no horns, are no better off' for teeth than 
the male deer ? The answer is : Both of them are, 
by nature, horned animals ; but the females have 
lost their horns because they would be not only 
useless but dangerous. The horns are indeed of no 
more use to the males, but they are less dangerous 
because the males are stronger. 

Thus in some animals this " part " a of the body 
is secreted for the formation of horns ; in others, 
however, it causes a general increase in the size of 
the teeth, and in others again it produces tusks, 
which are like horns springing out of the jaws 
instead of the head. 

We have now dealt with the " parts " that apper- 
tain to the head. 

III. The place of the neck, when there is one, is Of the 
below the head. I say " when there is one," because oefopv 
only those animals have this part which also have 



664 a 

\dplV 6 av\r)v 7T€(j)VK€V' Ta£>T(X S' IgTIV 6 T€ <f>dpvy£ 

Kal 6 KaXovfievog oloo(f>dyos . 

e O [lev ovv <f)dpvy^ rod Trvevfiaros eveKev ire^VKev 
hid rovrov yap eiadyerai to rrvevixa ret i^wa Kal 
€K7T€fi7T€L avairveovra Kal eKirveovra. hid rd fir) 

20 eyovra irXevpiova ovk exovoiv ot)S' avytva, otov 
to rwv lydvuiv yevos* 6 §' oloocfcdyos earl hi ov 
rj rpo<j)r) iropeverai eh rrjv KoiXlav tooB* oaa jlit) 
e%ei avyeva^ ovV olao<f)dyov eTTihrjXcos k'xovuiv. 
ovk avayKaiov 8* e^etP' rov oloocjydyov rfjs rpocf>rjs 
eveKev ovOev yap TrapaoKevd^ei irpds avrrjv. en 

25 he fierd rrjv rod OTopLaros Oeoiv evheyerai KeiaOai 
rrjv KoiXlav evOews, rov he irXevp.ova ovk evheyerai . 
Set yap etvaL riva koivov olov avX&va, hi ov fie- 
pieirai to Trvevpia Kara ras dprrjpias els ras 
cvpiyyaSy St/xepr} ovra 1, Kal /caAAioV av ovrcos 
airoreXoi rrjv dva7rvorjv Kal eKTrvorjv. rov 8' op- 

30 ydvov rov Trepl rrjv dva7rvorjv e| aydyKrjs eyovros 
firjKos, avayKaiov rov olaocj)dyov elvai fiera^v rod 
GTOfiarog Kal rrjs KoiXias. tori S' 6 piev olao<f)dyos 
oapKwhrjs, e^wi/ vevpcohrj rdoiv, vevpcohrjs fiev, 
ottojs eyrj hidraaiv elaiovGrjs rrjs rpo<f>rjs, aapKwhrjs 

35 he, onajg [xaXaKos fj Kal evhihco Kal firj fiXdirrrjrai 
rpayyvofievos vtto tqjv Kariovrwv, 

e H he KaXovfAevrj <f>dpvy£ Kal dprrjpla ovveGrrjKev 
664 b €/c xovhpcohovs vcofxaros' ov yap piovov avarrvorjs 
eveKev eoriv dXXd Kal (f>u)vrjs, hei he to ipo^rjGLiv 
fieXXov Xeiov elvai Kal orepeorrjra eyetv. KeTrai S' 
efJL7Tpoa6ev rj dprrjpla rov oloo<f>dyov > Kalirep ejx- 
TTohit.ovoa avrdv irepl rrjv vTTohoyrjv rrjs rpo<f>rjs' 
5 edv yap ri Trapeiapvfj £rjpov rj vypov els rr)v dprrj- 
1 hifjLtpf} ovra Peck : SifLeprjs u>v vulg. : Bifiepovs optos Th. 


those parts that the neck subserves — viz. the larynx 
and the oesophagus, as it is called. 

The larynx is present for the sake of the breath : 
when animals breathe in and out, the breath passes 
through the larynx. Thus creatures which have no 
lung (e.g. fish) have no neck either. The oesophagus 
is the passage by which the food makes its way to 
the stomach ; so those that have no neck have no 
distinct oesophagus. So far as food is concerned, 
however, an oesophagus is not necessary, since it 
exerts no action upon the food ; and there is really 
no reason why the stomach should not be placed 
immediately next the mouth. The lung, however, 
could not be so placed, because some sort of tube 
must be present, common to both lungs, and divided 
into two, by which the breath is divided along the 
bronchial tubes into the air-tubes : this is the best 
method for securing good breathing, both in and out. 
This respiratory organ, then, of necessity, is of some 
length ; and this necessitates the presence of an 
oesophagus, to connect the mouth to the stomach. 
Now the oesophagus is fleshy, and it can also be. 
extended like a sinew. It is sinewy so that it can 
stretch as the food enters in ; and it is fleshy so that 
it may be soft and yielding and not be damaged by 
the food grating on it as it goes down. 

What are called the larynx and windpipe are Larynx and 
constructed of cartilaginous substance, since the pur- ^^p 1 ? 3 * 
pose they serve includes speech as well as respira- 
tion ; and an instrument that is to produce sound 
must be smooth and firm. The windpipe is situated in 
front of the oesophagus, although it causes it some 
hindrance when food is being admitted — as when a 
piece of food, no matter whether solid or fluid, gets 


plav s rrviypovs Kal ttovovs Kal firjx a $ X a ^ e7T ^ 

ifjL7TOL€L. O hrj Kal 9aVfJL<10€L€V CLV TLS TO)V XeyovTWV 

cos" ravrrj to ttotov Se^erat to t>coov avp^aivei yap 
<f>avep{bs ra, Xe%9evTa rraoiv ois av rrapappvfj rt Trjs 
10 Tpo<f>rjs. TToXXaxfj oe yeXolov (fyauverai to Xeyeiv ojs 
ravTrj to ttotov etaSe^eTat ra £<£>a. nopos yap 
ovbels eonv els Trjv KoiXLav and tov rrXevpiovos, 

OJOTTep €K TOV GTOpiaTOS 6pWpeV TOV oloO<f)dyOV. 

€TL 8' iv tols epeTOis Kal vavTiais ovk ahrjXov rroQev 
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dAA' ooa rrXevpova e^ei Kal to oeppa Tpi^WTOv, Kal 

25 prj (^oAtSaJTa prjhe TTTepojTa Tre<f>VK€v. tovtols 8' 
avTl Trjs err tyXojTT loos ovvdyeTai Kal otolyeTai 6 
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Kal e£68oj avaiTTVOGopievos t Trjs oe Tpo<f>r)s elu- 

1 t,cooTOKOvvra\ £a)a tcl evaifxa Ogle. 
2 (n€v) supplevi et interpunctionem hie correxi. 



into the windpipe by mistake, and causes a great deal 
of choking and distress and violent coughing. This 
sort of thing occurs and can be observed whenever a 
piece of food goes the wrong way ; yet they must be 
mysteries to those who hold that animals take in their 
drink by way of the windpipe. a And there are many 
counts on which we can show that this is a ridiculous 
opinion to hold. («) There is no passage leading from 
the lung into the stomach, such as the oesophagus, 
which, as we can see, leads thither from the mouth. 
And again, (6) there is no doubt where the fluid dis- 
charge comes from in cases of vomiting and sea-sick- 
ness, (c) It is plain, too, that the fluid matter which 
we take does not collect immediately in the bladder, 
but goes first into the stomach. This is shown by 
the fact that the dregs of dark wine affect the co- 
lour of the residual discharge from the stomach ; and 
this colouring has often been observed in cases where 
the stomach has been wounded. Still, perhaps it is 
sill}' to be too minute in discussing these silly theories. 

The windpipe, as we have said, is situated in front, Epiglottis, 
and therefore is interfered with by the food. To deal 
with this difficulty, Nature has contrived the epi- 
glottis. Not all Vivipara b have this, but only those 
which have a lung, and a hairy skin, and are not 
covered with horny scales or feathers. Those that 
are so covered have, to serve instead of the epiglottis, 
a larynx which closes and opens, just as the epiglottis 
does in the others ; it comes down and lifts up again : 
it lifts up during the entrance and exit of the breath, 
and subsides while food is being taken, to prevent 

° See e.g. Plato, Timaeus 70 c 7, and Taylor ad loc. ^ 
b Ogle changes the text here to read " blooded animals, 
which brings the statement nearer the truth. 



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anything coming in by mistake into the windpipe. If 
there is any error in this movement, or if you breathe 
in while you are taking food, coughing and choking 
results, as I have said. But the movement of the 
epiglottis and of the tongue has been so neatly 
contrived that while the food is being masticated in 
the mouth and is passing over the epiglottis, the 
tongue seldom gets in the way of the teeth, and 
hardly ever does any food slip into the windpipe. 

I mentioned some animals that have no epiglottis. 
This is because their flesh is dry and their skin hard ; 
and thus if they had one, it would not move easily, 
because it would have to be made out of constituents 
of this sort. It is quicker to contract the edges of the 
windpipe itself than it would be to close an epiglottis, 
if, as in the hairy creatures, it were made out of the 
same sort of flesh as the rest of their bodies. 

This will suffice to show why some animals have an 
epiglottis and some not ; how Nature has contrived 
it so as *to remedy the unsatisfactory position of 
the windpipe in front of the oesophagus. Still, the 
windpipe is bound by necessity to be in this position 
for the following reason. The heart is situated in the 
middle of the body and in the fore part of it ; and in 
the heart, we hold, is the principle of life and of all 
movement and sensation. Both of these activities 
take place in the direction we call forwards : that is 
the very principle which constitutes the distinction 
between before and behind. The lung is situated in 
the region of the heart, and surrounding it. Now 
breathing takes place for the sake of the lung and 
the principle which is situated in the heart : and the 
breath passes through the windpipe. So, since the 




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SijXov S' Tot? veoyvois tovtcov alfiaTCoSiaTepa 
yap /cat fieyioTa Kara Adyov Sta to €tVat to etSos* 

a Limited by Aristotle to blood-like viscera only. 



heart must of necessity be situated in the front place 
of all, both the larynx and the windpipe, which lead 
to the lung and the heart, must of necessity be 
situated in front of the oesophagus which leads merely 
to the stomach. Speaking generally, unless some 
greater object interferes, that which is better and 
more honourable tends to be above rather than below, 
in front rather than at the back, and on the right side 
rather than on the left. 

We have now spoken of the neck, the oeso- 
phagus, and the windpipe, and our next topic is the 

IV. Only blooded animals have viscera. Some, but internal 
not all, have a complete set of them. As no blood- blooded 
less animals have them, Democritus must have been animals. 
wrong in his ideas on this point, if he really supposed 
that the viscera in bloodless creatures arc invisible 
owing to the smallness of the creatures themselves. 
Against this we can put the fact that the heart and 
the liver are visible in blooded animals as soon as they 
are formed at all, that is, when they are quite small : 
in eggs they are visible, just about the size of a point, 
sometimes as early as the third day, and very small 
ones are visible in aborted embryos. Further, just 
as each animal is equipped with those external parts 
which arc necessary to it for its manner of life and its 
motion, and no two animals require exactly the same 
ones, so it is with the internal parts : they vary in the 
various animals. 

Viscera, then, are peculiar to the blooded animals, Heart, 
and that is why each one of the viscera is formed of 
blood-like material. This is clearly to be seen in the 
new-born offspring of blooded animals ; in them the 
viscera are more blood-like, and at their largest in 



>b } ^ N 

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TioXXds dpxds Kal 8i€G7Taofi€vas 2 ttoiovgiv, elr iv 

1 lovaai Z. 2 ^Lca-Trap/ievas ESUYZ. 

° The first observer after Aristotle to realize the disparity 
in the relative sizes of the parts with time was Leonardo da 
Vinci (a.d. 1452-151S). 


proportion a : this is because the nature of the material 
and its bulk are especially obvious at the first stage 
of a creatures formation. The heart is present in 
all blooded animals, and the reason for this has been 
already stated ; It is obviously necessary for all 
blooded creatures to have blood, and as blood is a 
fluid, there must of necessity be a vessel to hold 
it, and it is evidently for this purpose that Nature 
has contrived the blood-vessels. And these blood- 
vessels must have a source — one source (one is 
always better than many where it is possible), and 
this source is the heart. This is certain, because the 
blood-vessels come out of the heart and do not pass 
through it ; and again, the heart is homogeneous and 
in character identical with the blood-vessels. Further- 
more, the place in which it is set is the place of 
primacy and governance. It is in a central position, 
and rather in the upper part of the body than the 
lower, and in front rather than at the back ; Nature 
always gives the more honourable place to the more 
honourable part, unless something more important 
prevents it. What I have just said is seen most 
clearly in the case of man, yet in other animals the 
heart tends in a similar way to be in the centre of 
the " necessary body," i.e. the portion of it which 
is terminated by the vent where the residues are 
discharged. The limbs vary in the various animals, 
and cannot be reckoned among the parts that are 
" necessary " for life, which is why animals can lose 
them and still remain alive ; and obviously they could 
have limbs added to them without being killed. 

Those who suppose that the source of the blood- 
vessels is in the head are wrong, because : (1) this 
involves holding that there are many sources, 



665 b 

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KapSlas ov hiaTelvei <f)Xeip- S9ev Kal hijXov ore 
fioptov Kal apXT] tcov (f>Xe ficov IgtIv r) Kaphia. Kal 
tout' evXoycos' p.eaov yap to Trj$ Kaphiag iarl 

35 crcofia ttvkvov Kal kolXov uecbvKog , en he. rrXrjpes 

666 a alfxaros cbs tcov (f>Xe^cov evTevOev rjpyjievcov , kolXov 

[lev rrpos Tr\v vrrohox^jv tov aL[iarog } ttvkvov he 

TTpOS TO (j>vXaOU€LV TTjV <lpX*} v rr }s OepflOTrjTOS . ev 

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6 atfia dvev tpXeficov euTi } tcov 8* dXXcov fiopicov 
€Kao~ov ev tols tfcXeiblv e^et to atfia. Kal tovt ev- 
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tcls tpXefias, els Se tt)v Kaphiav ovk dXXoOev- avTrj 
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TTpcoTTj. €K tcov dvaTOficov he KaTahrjXa fi&XXov 

io ray-a, Kal eK tcov yeveuecov evdecog yap euTiv 
evai\xos upcoTTj yivofidvrj tcov fiopicov drrdvTcov. e.Ti 
8' at KLvqaeig tcov rjhecov Kal tcov Xvnrjpcov Kal 
oXcos Ttdtjrjs aludrjaecos evTevOev dpxdfievai </>ai- 
vovTai Kal Trpos TavTrjv Trepalvovaai. ovtco 8* k'xei 
Kal KaTa tov Xoyov, dpxrjv ydp etvai hei fiiav, ottov 

is ivhex^Tai' ev<f)veoTaTos he. tcov tottcov 6 iievos, ev 
ydp to jieaov Kal errl ttcxv ithiKTov opLoicos rj Trapa- 
TrXrjGLCos. e.Ti 8' errel ovWe tcov dvaijicov ovQev 
1 Kal om. Z. 

a Or "traverse." The connotation of this term seems to vary. 


scattered about ; and (2) it involves placing them 
in a cold region (its intolerance of cold proves this). 
The region round the heart, on the other hand, is 
warm. And (3) as has been said alreadv, the blood- 
vessels run all through a the other viscera, whereas 
none passes through the heart ; which clearly shows 
that the heart forms part of the blood-vessels and 
is their source. Which is reasonable enough : since 
the centre of the heart is a body of dense and hollow 
structure, and this is full of blood ; it is hollow to 
form a receptacle for the blood ; dense to guard the 
source of heat ; and the store of blood is obviously 
there because that is the starting-point of the blood- 
vessels. In none other of the viscera and in no other 
part of the body is there blood and yet no blood- 
vessels ; in each of the other parts the blood is con- 
tained in blood-vessels. And this too is reasonable, 
as the blood is conveved and conducted away from 
the heart into the blood-vessels, whereas none is 
thus conveyed into the heart from elsewhere, for the 
heart is itself the source and spring of the blood, or 
the first receptacle of it. All this, however, is more 
clearly brought out in Dissections and Formative 
Processes, where it is shown that the heart is the 
first of all the parts to be formed and has blood in it 
straightway. Further, all motions of sensation, in- 
cluding those produced by what is pleasant and pain- 
ful, undoubtedly begin in the heart and have their 
final ending there. This is in accord with reason ; 
since, wherever possible, there must be one source 
only ; and the best situation for that is the centre, 
because there is only one centre, and the centre is 
equally (or nearly equally) accessible from every 
direction. Again, as every bloodless part, and the 



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to 7rpa)Tov evaLjxov, tolovtov 8' rj /capSta* Kal yap 

666 b dpxrj tov alfiaTos Kal evaLfiov irpGiTOV. 

"Ecrrt 8* avTrjs to aKpov d£t» /cat OTepewTepov, 
1 St* Th. : i£ vulg. ; mox ineivov EUYZ. 

° Cor primitm vivens ultimum morlens : cf. De gen, an. 
741 b 15 IF., and Ebstein & al., Mitt, z, Gesch. der Medizin u. 
Naturw,, 1920, 19, 102, 219, 305. » See 655 b 29, n. 



blood itself as well, is without sensation, it is clear 
that the part where the blood is present first, and 
which holds it as in a receptacle, must of necessity be 
the source. 

This reasoning is supported by the evidence of 
the senses. In embryos, as soon as they are formed, 
the heart can be seen moving before any of the 
other parts, just like a living creature a ; which 
shows that it is the source of their nature in all 
blooded animals. Another piece of evidence to 
support this is that all blooded creatures have a 
heart : why ? because they are bound to have a 
source for their blood. All blooded creatures, it is 
true, have a liver too ; but no one would care to 
maintain that the liver is the source either of the 
blood or of the whole body, because it is nowhere near 
the place of primacy and governance, and, also, in 
the most highly finished b animals it has something 
to counterbalance it, as it were, viz. the spleen. 
Again, the liver has no receptacle for blood in itself 
as the heart has : like the rest of the viscera, it keeps 
its blood in a blood-vessel. Again, a blood-vessel 
runs all through it, whereas no blood-vessel runs 
through the heart : all blood-vessels have their source 
from the heart and begin there. Since, therefore, of 
necessity the source must be one of these two, the 
heart or the liver, and as it is not the liver, it must of 
necessity be the heart which is the source of the blood 
just as it is of the rest. An animal is defined by the 
fact that it possesses sensation : and the part of the 
body to have sensation first is the part that has blood 
in it first — in other words, the heart, which is the 
source of the blood and the first part to have it. 

The apex of the heart is sharp and more solid than 



666 b 

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rod acofxarog irpos to fxr) Karaifjvxeodai avro' iraoi 
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Seorepa, Bio TroXXrjv eye^ gkIttt^v to Oeppiov Kara 

TOV VWTOV. €GTl 8* T) KCLphla TOt? fXeV dXXoiS ^01? 

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pLLKpov els to, evwvvfia TrapeKKXlvovcra npos to 
dviaovv ttjv Kardifjv^iv rcov dpiOTepwv {xaXiura yap 

10 tcjv aXXojv ^coojv avOpcoTros e%ei Karei/jvyfieva ra 
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"E^et Be Kal vevpojv TrXrjdos f) KapBia, Kal toOt' 

15 evXoytos* diro TavTTjs yap at Kivrjoeis, rrepaivovTai 
Be Bid tov eXtceiv Kai dvievar Bel ovv ToiavTrjs 
V7TT]peoLas Kal to^uo?. r) Be KapBia, KaBdrrep 
eiTTopLfV Kal irpoTepov, otov £cooV tl Tre(f)VKev ev 
tols eyovoiv* 

"Eon 8* dvouTeos TidvT<x>v oca Kal r}p.els Teded- 
fieda, TrXrjv tcov lttttcdv Kal yevovs twos fiowv 

20 rouTots" Be Bid to fieyeOos otov epeiafiaTOS X^P lv 
ootovv vireoTi, Kaddrrep Kal toIs oXois oojpLaoiv. 

KotAta? 8' eypvuiv at f.iev tqjv fieydXwv £wojv 
TpeiSj at Be tcjv iXaaooviov Bvo, puiav Be rraoai' Bi 
rjv 8' aiTiav, elpr\Tai. Bel yap elvai tottov Tivd Trjs 

° At De respir. 478 b 3. And see the next note. 

6 Instead of towards the breast. The meaning of this 
passage is made dear by Hist. An. 507 a 2 ff . In all animals, 
says Aristotle, the 44 apex " of the heart points forwards, and 
in most animals " forwards " is towards the breast. Fishes 



the rest, and it lies towards the breast, and altogether 
in the fore part of the body so as to prevent it from 
getting cooled : for in all animals the breast has com- 
paratively little flesh on it, while the back is well 
supplied and so gives the heat of the body ample 
protection on that side. In animals other than man 
the heart is in the centre of the region of the breast ; 
in man it inclines slightly to the left side so as to 
counteract the cooling there, for in man the left side 
is much colder than in other creatures. I have 
said already that the placing of the heart is the 
same in fishes as in other animals, though it appears 
to be different, together with the reasons a for the 
apparent difference. In fishes its apex is turned to- 
wards the head b ; but in them the head is " forwards/' 
because the head is in the line of direction in which 
they move. 

The heart has in it an abundance of sinews, which 
is reasonable enough, as the motions of the body have 
their origin there ; and as these are performed by 
contraction and relaxation, the heart needs the sinews 
to serve it and to give it strength. We have said 
already that the heart is like a living creature inside 
the body that contains it. 

In all cases that we have examined the heart is 
boneless, except in horses and a certain kind of ox. 
In these, owing to its great size, the heart has a bone 
for a support, just as the whole body is supported 
by bones. 

In the large animals, the heart has three cavities, in 
the smaller ones, two only ; and in no species has it less 
than one. The reason for this has been given : there 

appear to be an exception to this rule, but only because in 
them *' forwards " is towards the head. 



666 b f ^ y f v 

Kaphias Kal vttooox^v rod irpwrov alfxaros, (on 

25 8 € TTpGiTOV kv TTj KGLpSla yLV€TOLl TO atfJLCL, 7ToX\oLKLS 

elp-qKafjiev.) Sta, Se 1 to rag dpx^yovg (frXiftag hvo 
etvai, rr\v re fjLeydXrjv KaXovfiivrjv Kal rrjv aopr-qv, 
€Karepag S* 2 ovaiqg dpx^js rcbv <^>Aej8cuv, Kal Sta- 
cf>opds ixovucbv, 7T€pl cov vorepov ipovfiev, fiiXnov 
Kal rag dpxdg avrwv /cexajptatfar rovro S' av etrj 

30 hi(f)vovg ovros rod at/xaros Kal /ce^ajptctyteVou. 
StoVep iv otg eVSe'^erat, elalv u-n-oSo^at. iv- 
Se'^erat 8' iv rots ueyaAot?* rovrcov yap £X 0VGl Ka ^ L 
at /capStat fiiyedog. en Se fieXrtov rpelg etvat rag 
KotXlag, ottojs fj uta apxV Koivq- to Se fieaov /cat 
TrepiTTov apxtf' ware fieyeOovg Set iazL^ovos avralg 

35 det, StoVep at fieyiarai rpecg e^ouat /xoVat. 

667 a Toutojv Se 7rAetarov uey atua /cat Oepfiorarov 

exovoiv at Se£tat (Sto /cat rcDy [A€pojv depfiorepa ra 
Se£td), eAa^toroy Se /cat tfjvxpdrepov at dptorepat, 
fieGov 8 s at \iioai ra> rrXr^^i Kal OepfJLorrjri, KaOa- 
pwrarov Se* Set yap tt)v dpxrjv ° Tt ^taAtar' i]pe/xea>, 

5 roiavrrj 8' aV eoj KaBapov rod aifiarog ovros, rw 
7rXrj6€L Se /cat Ozpfiorrjri fiioov. 

"E^ouot Se /cat hidpBpojoLv riva at /capStat napa- 
TrXiqaiav ralg pacf>ais. ovk etat Se ovva<j>eis a>g 
rivog e/c 77Aetdva»v ovvOerov, dXXd KaOdirep €lt70/jl€V, 
hiap6pd>o€i fiaXXov. etat Se tow juey alcrOrjriKcov 

io dpOpajhiurepaL, rcov Se vcoBporipcov dvapBporepai, 

1 SiaSeESUYZ: Suxvulg. 
2 8' Peck : yap vulg., om. Ogle. 



must be some place in the heart which will be a 
receptacle for the blood when first formed. (As we 
have stated several times, blood is first formed in 
the heart.) Now there are two chief blood-vessels, 
the so-called (3reat Blood-vessel, and the Aorta ; each 
of these is the source of other blood-vessels ; and 
the two differ from each other (this will be discussed 
later) ; hence it is better for them to have separate 
sources. This result can be obtained by having two 
separate supplies of blood, and thus we find two 
receptacles wherever this is possible, as in the larger 
animals which of course have large hearts. But it is 
better still to have three cavities, and then there is 
an odd one in the middle which can be a common 
source for the other two ; since, however, this requires 
the heart to be particularly large, only the very 
largest hearts have three cavities. 

Of these cavities it is the right-hand one which 
contains the most blood and the hottest (that is why 
the right side of the body is hotter than the left) ; 
the left-hand cavity contains least blood, and it is 
colder. The blood in the middle cavity is inter- 
mediate both in amount and heat, although it is the 
purest of them all ; this is because the source must 
remain as calm as possible, and this is secured when 
the blood is pure, and intermediate in its amount and 

The heart has also a sort of articulation, which 
resembles the sutures of the skull. By this I do not 
mean to say that the heart is a composite thing, 
consisting of several parts joined together, but an 
articulated whole, as I said. This articulation is more 
distinct in animals whose sensation is keen, and less 
distinct in the duller ones, such as swine. There are 



j a 

KaOdirep al tojv vcov. al 8e Sia<j>opal ttjs KapSlas 
Kara piyeOos re Kal piKpoTrjra Kal GKXrjporrjra re 
Kal paXaKor-qra Telvoval ttt] Kal irpos ra rjdrj- ra 
fiev yap avalod-qra oKXr)pdv e^et ttjv Kaphlav Kat 
15 TTVKvrjv, ra, 8' alaOrjTtKa paXaKOJTepav, Kal ra pev 
peydXas exovra ras KapSlag SeiAa, ra 8* iXaacrovs 
Kal piaas OappaXeojrepa (to yap avpfiatvov rrdSos 

V7TO TOV <j>Op€L(70aL TTpOVTrdpX^ TOVTOtS Old TO p7] 

dvdXoyov ex elv T ° @epfJ-ov rfj /capSta, ptKpov 8' 6V 
iv peydXois dpavpovaOat, Kal to alpa ipv^porepov 

20 elvai) . peydXas 8e rd$ Kaphias e^oucrt Xayws, 
eXarpos, pvs, vaiva, ovo$, TrapSaAis"/ yaXfj, Kal 
TaAAa a^eSo^ irdvO^ oaa cfraveptos SeiAa. r) Sia 
<f)6fiov KaKovpya. 

UapaTTXrjaloJS oe Kal €ttI tojv (fjXzfiwv Kat irrl 
tojv kolXlojv e^er ipv^pal yap al peydXai (ftXefies 

25 Kal KoiXiai. axjirep yap iv ptKpto Kal iv peydX(p 
olKTjpaTi to laov TTVp rjacrov iv toi$ petioai 6ep~ 
paivet, ovro) Kav tovtols to Oeppov dyyela yap 
Kal r) <f)Xeip Kal rj KotXta. IVi 8' at aAAoVpiai Ktvrj- 
CF€is €Kaorov tojv Oeppcov Karaifjv)(OVGLV, iv Se Tals 
evpvxojpearepais to irvevpa irXeiov Kal ivta)(V€t 

30 paXX.ov 8to tojv peyaXoKoiXiojv ovSev ovoe tojv 
pey aXocjjXi fiojv ttiov ion Kara crdpKa, dXXa irdvra 
rj Ta TrXeto-ra tojv tolovtojv a8^Ad^Ae^a Kal piKpo- 
ko iXia (jjalverat, 

MoVov 8e tojv oTrXdyxvojv Kal SXcos tojv iv toj 
1 -napha\i$\ BopKaXts Piatt. 



other differences in the heart ; some hearts are large, 
some small, some are hard, some soft ; and these 
tend by some means to influence the creature's 
temperament. Illustrations of this are : animals 
whose powers of sensation are small have hearts that 
are hard and dense, those whose sensation is keen 
have softer ones ; and those with large hearts are 
cowardly, those with small or moderate-sized ones, 
courageous (this is because in the former class the 
affection which is normally produced by fear is 
present to begin with/ 1 as their heat is not proportion- 
ate to the size of their heart, but is small and there- 
fore hardly noticeable in the enormous space that it 
occupies ; so that their blood is comparatively cold). 
The following creatures have large hearts : the hare, 
the deer, the mouse, the hyena, the ass, the leopard, 
the marten, and practically all other animals whose 
cowardice is either outright or else betrayed by their 
mischievous behaviour. 

Similar conditions obtain in the blood-vessels and 
the cavities of the heart : if they are large, they are 
cold. The effect of the same-sized fire is less in a 
large room than in a small one ; and the same applies 
to the heat in these receptacles, the blood-vessels and 
the cavities. Further, extraneous motions have a 
cooling effect upon hot things ; and the more roomy 
a receptacle is, the greater the amount of air (or 
pneuma) in it and the stronger its effect. Thus we 
find that no animal which has large cavities or large 
blood-vessels has fat flesh, and conversely, that all (or 
most) fat animals have indistinguishable blood-vessels 
and small cavities. 

The heart is the only one of the viscera — indeed 

° Cf. 650 b 27. See also 692 a 20. 



667 a 

acofMOLTi fxopLCov 7] Kaphla xaXeirov irddos ovhev 
viTO^epei, Kal tout' €v\6ya>s' (frdeipofjLevrjs yap rrjg 
35 CLpX*)s 0VK €<mv it; ov yivoiT av fio-qOeia rots 

667 b aXXotS €K TaVTTjS r)pT7JfJL€VOLS . G7JfJL€LOV 0€ TOV 

fxrjOev eVtSe^ea^at irdOos ttjv Kaphlav to iv fxrjhevl 
tqjv Ovofiivcov Upelajv <L<f>dai tolovtov 7rddo$ irepl 
avTTjv a>G7T€p inl tqjv aXXcov oiiKdyyycov \ 61 re 
yap ve(f>pol ttoXX&kls (f>aLi'ovrai XlOojv fxearol Kal 
5 (f)VfJLdr ojv Kal SoOtrjvojv Kal to rjirap, ujaavTOis oe 
Kal 6 tt\€V{jlcov, ixaXiora 8' 6 onXrjv. 7roAAa Se /cat 
erepa 7ra6rjfiara av/JL^atvovra irepl avrd (fraiverai, 

7)KlGTa §€ TOV fJL€V TrXeVpLOVOS 7T€pl TTjV dpTrjplav, 

tov 8' TjiraTOS 77e/H Trjv ovvaifjiv Tjj fxeydXr) <£Ae/?t, 
io Kal tovt evXoycos* TavTrj yap /xaAiora kolvojvovol 
tt) /capSta. ooa Se Sta. voaov Kal TOtavTa irdOr] 
<^atWrat TeXevTCovTa tujv ^ojojv, tovtols dvaTefivo- 
fxevots <j)alv€Tai irepl tt)v KaphLav vooa)Srj irdBf). 
Kat \ikv Trjs KapSlas, rroia tls, Kal tLvos 

€V€K€V Kal StO. TIV atTtW V7TOLp^€L TOLS €)(OVOLV, 

ToaavT eiprjoOa). 

15 V. f E77o/x€vov 8' av €L7] rrepl twv cfaXefiwv etVetv, 
Trjs re fxeydXrjs Kal Trjs aopTrjs* avTai ydp €K Trjs 
KapBias TrpwTai S^ovtcu to af/xa, at Se Aotmu 
tovtwv dirocfrvdhes elolv. on fiev ovv tov alfxaTOS 
xdpw elai, irpoTepov etprjTai- to tg yap vypov ai:av 

20 dyyeiov SeiTat, Kal to <f)Xe^a>v y£vo$ dyyetov, to 8' 


the only part in the whole body — which cannot 
withstand any serious affection. This is readily 
understood : the other parts depend upon the heart, 
and when this source itself is ailing, there is no place 
whence they can obtain succour. A proof that the 
heart cannot put up with any affection is this : Never 
has the heart in a sacrificial victim been observed 
to be affected in the way that the other viscera 
sometimes are. Very often the kidneys are found 
to be full of stones, growths, and small abscesses ; 
so is the liver, and the lung, and especially the 
spleen. Many other affections are observed in 
these organs ; but in the lung they occur least 
often in that portion which is nearest the windpipe, 
and in the liver in that portion which is nearest its 
junction with the Great Blood-vessel. This is readily 
understood : those are the places where they are 
most closely in communication with the heart. 
Those animals, however, which die as the result 
of disease, and affections such as I have mentioned, 
when cut open are seen to have diseased affections 
of the heart. 

We have now spoken of the heart : we have said 
what its nature is, what purpose it serves, and why it 
is present ; and that will suffice. 

V. I suppose that the next subject for us to discuss Blood- 
is the Blood-vessels, that is, the Great Blood-vesseP esse 9 
and the Aorta. It is these into which the blood 
goes first after it leaves the heart, and the other 
blood-vessels are merely branches from these. We 
have already said that these blood-vessels are present 
for the sake of the blood : fluid substances always 
need a receptacle, and the blood-vessels generally 
are the receptacles which hold the blood. We may 



667 b 

at/xa £v ravracs' Slotl 8e Bvo Kal drro /xta? dpx^js 
kglO* duav to atopa StareiVofat, Xiywpev. 

Tov p,ev ovv els fJLtav apx^jv avvreXelv Kal and 


4 fV XV v € v €py^ a > cScrre Kal to popiov ev to tolvttjv 


25 Kal /<rar' ivipyeiav s twv 8' dvaipojv ivlois Kar' 
ivipy eiav fiovov), olo Kal ttjv tov Beppov dpx^jv 
avayKalov iv to> aura) to7to) elvac avTTj 8* iarlv 
atTta Kal tco alfiaTL Trjs vypoTrjTos Kal Trjs 8ep- 

fJLOT7)TOS. StOL jJ,€V OVV TO €V ivl €LVai fLOpiW TTjV 

ala9r]TLKrjv apXV v Ka * L T W r V$ OeppoTrjTOS Kal rj 
30 tov alfiaTOS drro puds IotIv dpxrjs> Sta. 8e Tr)v tov 
alpaTOS IvoTryra Kal r) tcov cjyXefitov drro /xtas". 

Avo 8' elal Sta to to. oajpaTa elvai hipepr) tcov 
ivalpwv Kal rropevTiKtov Iv rrdui yap tovtols 
Stojptcrrat to eprrpooOev Kal to ottloQzv Kal to 
Se^ioy Kal to dpiGT€p6v Kal to dvoj Kal to kcltlo. 

35 OUCl) Se TipLCOT€pOV Kal r)y€piOVLKCOT€pOV TO €p~ 

668 a Trpoodev tov OTTLoOeVj togovto) Kal r) jjceydXt] <j)Xetp 

Trjs dopTrjs' r) fJLev yap iv tols 'iprrpoaBev, r) 8" iv 

TOLS 67TtO0€V K€LTaL } Kal TTjV jJL€V dlTaVT I'^et T(X 

evaipa tfiavepws, rr)v 8' eVta pev dpvSptos Zvia S* 

Tov 8' els to Trav StaSeSocr#at to ucdpa Tas 
5 (f>Xifias aiTiov to rravTOS etvai tov crtopaTos vXr)v 
to at/xa, Tot? 8' dvaipois to dvdXoyov, raura 8' iv 

a And potentially many ; c/. 682 a 4 ff . 



now go on to explain why there are two of these blood- 
vessels, why they begin from a single source, and why 
they extend all over the body. 

The reason why finally they both coincide in one 
source and also begin from one source is this. The 
sensory Soul is, in all animals, one actually ; there- 
fore the part which primarily contains this Soul is 
also one (one potentially as well as actually in the 
blooded animals, but in some of the bloodless animals 
it is only actually one a ), and for this reason the source 
of heat also must of necessity be in the selfsame 
place. But this concerns the blood, for this source 
is the cause of the blood's heat and fluidity. Tims 
we see that because the source of sensation and the 
source of heat are in one and the same part, the blood 
must originate from one source too ; and because 
there is this one origin of the blood, the blood-vessels 
also must originate from one source. 

The blood-vessels are, however, two in number, be- 
cause the bodies of the blooded creatures that move 
about are bilateral : we can distinguish in all of 
them front and back, right and left, upper and lower. 
And just as the fore part is more honourable and 
more suited to rule than the back part, so is the Great 
Blood-vessel pre-eminent over the Aorta. The Great 
Blood-vessel lies in front, while the Aorta is at the 
back. All blooded creatures have a Great Blood- 
vessel, plainly visible ; but in some of them the Aorta 
is indistinct and in others it cannot be detected. 

The reason why the blood-vessels are distributed 
all over the body is that blood (and in bloodless 
creatures, its counterpart) is the material out of 
which the whole body is constructed, and blood- 
vessels (and their counterparts) are the channels in 




(j>Xepi Kal tco avaXoyov /cetcr#at. nebs p<ev ovv 
rpe^erai ra £cba /cat e/c rlvos Kal rlva rponov 
avaXajifidvovoiv e/c rrjs KoiXLas ev rots nepl yeve- 
oecos Xoyois jxaXXov ao/xd£et oKonetv Kal Xeyeiv. 
10 \YiWiUTayLevwv he rcbv pLopicov e/c rov atpLaros, 

KaOdnep €L7TOfJL€V t evXoytOS Tj TCOV <f>Xefitbv pVGLS 

hid navros rod otopLaros ne(f>VKev Set yap Kal to 
at/xa Sta navros Kal rrapa nav elvai 3 einep rcbv /xo- 
picov eKaorov e/vr rovrov ovvearrjKev.] 1 

"Eot/ce S' toonep ev re rots K-qnois al vhpayojylai 

15 Kar auKevd^ovr ai dno puds dp)(T}$ KaL 777 ?y^S" els 
ttoXXovs ox^tovs f<al dXXovs del npos to ndvrrj 
/xeTaStSdVat, Kal ev rals ot/coSo/itats 1 napa naaav 
rr)v rcbv BepLeXiCDv vnoypa<f>r)v Xldoi napaf$efiXr}vr ai, 
Std rd ra fiev Krjnevofieva tfiveaOai e'/c rod vSaros* 
rovs he OefxeXlovs e/c rcbv Xcdcov ot/coSo/xetcr#at, rov 

20 avrov rponov Kal r) cpvois to at/xa hid navros 
ci^ereu/ce rov acbfJLaros, enethr) navros vXt) necpVKe 
rovro. ylverat Se KardhrjXov ev rots pdXiara Kara- 
XeXenrvopievoLS' ovSev yap dXXo <f>aLverai napa ras 
tf>Xefias, KaOdnep enl rcbv dpcneXlvcov re Kal gvklvcov 

25 cfvXXcov Kal do* aAAa roiavra' Kal yap rovrcov 
avaLVOfievtov 2 <f>Xej3es XeLnovrai jiovov. rovrcov S' 
alriov on to aifia Kal to dvdXoyov rovrcp hwdfiec 
ucbfia Kal odpi; rj to dvdXoyov eanv KaOdnep ovv 

1 11. 10-13, quae praecedentia 1). 4-7 repetunt, secludenda. 

2 avaaofxevcov attice Bekker. 

a This seems to be an unnecessary repetition of the last 
sentence but one. 



which this material is carried. As regards the 
manner in which animals are nourished, the source 
of the nourishment, and the processes by which 
they take it up from the stomach, it is more appro- 
priate to consider these subjects and to discuss them 
in the treatise on Generation. 

[But since the parts of the body are composed 
out of blood, as has been said, it is easy to see why 
the course of the blood-vessels passes throughout 
the whole body. The blood must be everywhere 
in the body and everywhere at hand if every one of 
the parts is constructed out of it.] a 

The system of blood-vessels in the body may be 
compared to those water-courses which are con- 
structed in gardens : they start from one source, 
or spring, and branch off into numerous channels, 
and then into still more, and so on progressively, so 
as to carry a supply to every part of the garden. 
And again, when a house is being built, supplies of 
stones are placed all alongside the lines of the 
foundations. These things are done because (a) 
water is the material out of which the plants in the 
garden grow, and (6) stones are the material out of 
which the foundations are built. In the same way, 
Nature has provided for the irrigation of the whole 
body with blood, because blood is the material out 
of which it is all made. This becomes evident in 
cases of severe emaciation, when nothing is to be 
seen but the blood-vessels : just as the leaves of vines 
and fig-trees and similar plants, when they wither, 
leave behind nothing but the veins. The explana- 
tion of this is that the blood (or its counterpart) is, 
potentially, the body (that is, flesh— or its counter- 
part). Thus, just as in the irrigation system the 

I 251 


668 a 

iv rats o^eretats at pLeyiarai rcov rd(f>pa)V Sia- 
fiivovGLV, al S' eXd^iorai Trpcorai /cat ra^ecos vtto 
ri]$ IXvos d<f>avt{,ovrai, TrdXiv S* eKXeiTTovurjs 
30 <j>avepal ylvovrai } rov avrov rpoitov /cat rcov <f>Xe^cov 
at {lev \ieyiurai Sta/xeVoucrtv, at S' eAa^toTat yL- 
vovrai udpKes ivepyela s hwdfiei S' etcrtv ovhev 
rjtroov (frXepes. Sto /cat Gco^ofievcov rcov oapKcov 
kql9* otlovv aXpLa pet hcaLpovfievcov kclLtoi dvev [lev 
<f>Xef}6g ovk euriv af/xa, cffXefiiov 1 S' ovhev SrjXov, 

35 OXJ7T€p OuS' iv TOLS Octrois at rd(f)pOL TTplV rj TTjV 

668 b IXvv i^aipedrjvai. 

'E/c fiei^ovcov S' els eXdcraovs al c/yXe^es del 
upoepypvrai etas rov yeveoOai tovs iropovs iXdo- 
aovs rrjs rov alpLaros Traxvrrjros' St' cov rco [lev 
atjaart hlohos ovk eon, rco he ire pirrcofiarL rrjs 
vypas LKfjidSos, ov KaXovyiev lhpcora y /cat rovro 
5 hiaBepfiavOevros rov ocofiaros /cat rcov <j>Xefiitov 
dvaaroficoOevrcov, rjhrj he rtaiv Ihpcooai ovvefir) 
alfxarcohei irepirrcop^ari hid Kaye^iav y rov fiev 
acopcaros pvdhos /cat fiavov yevopiivov, rov S' at- 
fiaros i^vypavOivros St 5 drreipiav, dhvvarovorjs rrjs 
iv rots (frXe/StoLS OeppLorrjros Treooeiv hi oXiyorrjra. 
10 (eiprjrai yap on irav rb kolvov yrjs /cat vharos 
rrayyverai ireoGOfievov , rj oe rpo<f>r] /cat ro atfia 
piiKrdv e£ dfjicfjoiv.) dhvvarel he ireoueiv r) OeppLorrjs 
ov \xovov hid rr\v avrrjs oXiyor-qra dAAa /cat hid 
rrXrjOos /cat V7TepfioXr}V rrjs elacfrepopLevrjs rpo<f>rjs' 
1 (frXefHtov Bekker. 

a Could Aristotle have seen a case of haematoporphyria ? 


biggest channels persist whereas the smallest ones 
quickly get obliterated by the mud, though when 
the mud abates they reappear ; so in the body the 
largest blood-vessels persist, while the smallest ones 
become flesh in actuality, though potentially they 
are blood-vessels as much as ever before. Accordingly 
we find that, as long as the flesh is in a sound con- 
dition, wherever it is cut, blood will flow ; and 
although no blood-vessels are visible, they must be 
there (because we cannot have blood without blood- 
vessels) — just as the irrigating channels are there 
right enough, but are not visible until they are 
cleared of mud. 

The blood-vessels get progressively smaller as they 
go on until their channel is too small for the blood 
to pass through. But, although the blood cannot 
get through them, the residue of the fluid moisture, 
which we call sweat, can do so, and this happens when 
the body is thoroughly heated and the blood-vessels 
open wider at their mouths. In some cases, the sweat 
consists of a blood-like residue a : this is due to a bad 
general condition, in which the body has become loose 
and flabby, and the blood watery owing to insufficient 
concoction, which in its turn is due to the weakness 
and scantiness of the heat in the small blood-vessels. 
(We have already said that all compounds of earth 
and water are thickened by concoction, and this cate- 
gory includes food and blood.) The heat may, as 
I say, be in itself too scanty to be able to cause 
concoction, or it may be that it is scanty in comparison 
with the amount of food that enters the body, if 

See A. E. Garrod, Inborn Errors of Metabolism, Oxford, 1923, 
pp. 136 ff. Also H. Giinther, Deutsches Archiv f. klin. 
Medizin, 1920, 134, PP- 257 ff. 



668 b 

ylverai Be TTpos ravrrjv oXlyrj. r) 8' VTrepfioXr) 
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ofiolcos €V7T€7ttov. (pel Be. ^aAtara to atua Kara 
tovs cvpv^copearaTovs tcov Tropcov Biorrep e/c tcov 


koll ihc rod arofxaros alfjioppoihes airovoi ylvovrac, 
/cat ot>x couuep €K Trjs dpTrjpias [l€TOL jStas.) 

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doprr), Karoo 8* ivaXXdooovocu avvexovai r ® ocofxa. 
7TpOLOvaaL yap ax^ovrai /cara rrjv Bitf>vtav tcov 
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rrjs tcov tfiXeficov ivaXXd£ecos avvBecTai tcov acofxd- 
tcov Ta TTpoadia tols omadev. 6[aoloj$ Be /cat aVo 
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30 eK re tcov dvaTOficov Bel Qecopelv /cat e/c rr)s ^cdiKrjs 
lot op las. 

Kat irepl fxev cf>Xef3tov /cat KapBlas elprjadco, 
Trepl Be tcov dXXcov GTrXdyxvcov UKeixTeov Kara ttjv 
avrrjv fieOoBov. 

VI. UXevfiova {lev ovv k'xei Bid to iretov elval tl 
yevos tcov c^cpcov. dvayKacov p.kv yap ylveaOai tco 
85 Oeppup Kardipv^LVy ravrrjs Be 8etrat OvpaOev Ta 

669 a evacfia tcov ^cocov Oepp-drepa ydp. ra Be fir) evaifia 

° The posterior vena cava. 
b Hist. An., especially 511 b 11 — 515 a 26. 



this is excessive ; and this excess may be due either 
to the quantity of it or (since some substances are 
less patient of concoction than others) to its quality. 
(Haemorrhage occurs most where the passages are 
widest, as from the nostrils, the gums and the 
fundament, and occasionally from the mouth. At 
these places it is not painful ; when, however, it 
occurs from the windpipe, it is violent.) 

The Great Blood-vessel a and the Aorta, which in 
the upper part are some distance from each other, 
lower down change sides, and thus hold the body 
compact. That is to say, when they reach the place 
where the legs diverge, they divide into two, and 
the Great Blood-vessel goes over to the back from 
the front, and the Aorta to the front from the back ; 
and thus they unite the body together, for this 
changing over of the blood-vessels binds together 
the front and the back of the body just as the cross- 
ing of the strands in plaiting or twining makes the 
material hold together more stoutly. A similar 
thing occurs in the upper part of the body, where 
the blood-vessels that lead from the heart are inter- 
changed. For an exact description of the relative 
disposition of the blood-vessels, the treatises on 
Anatomy and the Researches upon Animals b should be 

We have now finished our discussion of the heart 
and the blood-vessels, and we must go on to consider 
the remaining viscera on the same lines. 

VI. First the Lung. The reason why any group of Lung, 
animals possesses a lung is because they are land- 
creatures. It is necessary to have some means for 
cooling the heat of the body ; and blooded animals 
are so hot that this cooling must come from outside 




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jxrjokv ovufidXXeadai rov TrXevfiova rrpos rrjv dXoiv 
rrjs /capStas 1 . 

Aia<j)ep€L §' 6 TrXevjxwv ttoXv toi$ £wol$. rd jiev 

° See above, on 659 b 17. 6 476 a 6. 

c See above, on 650 b 19 ff. 
d This view is expressed byTimaeus in Plato's Timaeus> 70c. 


them, though the bloodless ones can do their own 
cooling by means of the connate pneuma. a Now 
external cooling must be effected either by water or 
by air. This explains why none of the fishes has 
a lung. They are water-cooled, and instead of a 
lung they have gills (see the treatise on Respiration)* 
Animals that breathe, on the other hand, are air- 
cooled, and so they all have a lung. All land-animals 
breathe ; so do some of the water-animals (e.g. the 
whale, the dolphin, and all the spouting cetacea). 
This is not surprising, for many animals are inter- 
mediate between the two : some that are land- 
animals and breathe spend most of their time in the 
water owing to the blend c in their bodies ; and 
some of the water-animals partake of the nature of 
land-animals to such an extent that the limiting 
condition of life for them lies in their breath. 

Now the organ of breathing is the lung. It has 
its source of motion in the heart, and it affords a 
wide space for the breath to come into because it is 
large and spongy : when the lung rises up, the 
breath rushes in, and when it contracts the breath 
goes out again. The theory d that the lung is pro- 
vided as a cushion for the throbbings of the heart is 
not correct. This leaping of the heart is practically 
not found except in man, and that is because man is 
the only animal that has hope and expectation of 
the future. Besides, in most animals the heart is 
a long way off from the lung and lies well above 
it, and so the lung cannot be of any assistance in 
absorbing the throbbings of the heart. 6 

There are many differences in the lung. Some 

* In quadrupeds the lung is above the heart, but not in 
man, owing to the difference of posture. 



669 a 

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35 Sto Kal dSiipa Kal oXiyorroTa rayra irdvTa, /cat 
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crea)?, ovtos depoj^ovs Kal K€vov} 

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ttoSqjv ouSev yap ofiottos TpcoyXo8vT€i tcov £a)o- 
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"OXcos pLev ovv 6 TrXevjicov €gtIv dvarrvorjs xp-P lv i 
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10 aAA' dvwvvfiov to kolvov eV avTcov s Kal oi>x cooirep 

1 ovtos . . . Kevov Thurot : ovcnjs , , . Ktvfjs vulg. 
a Cf. 653 a 30 ff. 


animals have a large lung, which contains blood ; 
others a small one and spongy. In the Vivipara it is 
large and has much blood in it because these creatures 
have a hot nature : in the Ovipara it is dry and small, 
but it can expand to a great size when inflated : 
examples of these are : among land -animals, the 
oviparous quadrupeds like the lizards, tortoises, and 
all such creatures, and in addition to these the 
tribe of winged things, the birds. All these have a 
spongy lung, which, like froth, runs together and 
contracts from a large volume into a small one. So 
it counts as small ; and also it is membranous. As a 
result, all these creatures are not much subject to 
thirst, and drink but little ; and also they can bear to 
remain a long time under the water : this is because 
their heat is scanty and can therefore be sufficiently 
cooled over a long period by the mere motion of the 
lung, which is void and air-likc. 

(Consequently, one may add, in general these 
creatures are smaller in size than the majority of 
animals, as growth is promoted by heat, and a plenti- 
ful supply of blood is a sign that heat is present. 
Furthermore, heat tends to make the body upright, 3 
which explains why man is the most upright among 
the animals and the Vivipara the most upright among 
the quadrupeds. And there are no viviparous 
creatures, either with or without feet, so fond of 
creeping into holes as the Ovipara are.) 

The lung, then, is present for the sake of the 
breathing : this is its function always. Sometimes, 
to serve the purpose of a particular group, it is blood- 
less, and such as has been described above. There 
is no common name which is applied to all animals 
that have lungs. But there ought to be : because 

i 2 259 


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opvcdc etvat €K rivos e'ort, Kal eVetvojv iv rfj ovala 
virdpx^ to rrXevfxova e^etv. 

VII. Ao/cet Se t&v OTrXdyxvajv ra fiev etvat 
fiovo(f)vrj, KaOdrrep Kaphla Kal TrXevfXCtiV, ra he 

15 huj>vrj y KaBdrrep ve<j)poi s ra S' drropelraL rroripcos 
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Kal ws dv9* evos hvo TrapaTrXrjoiav exovra rrjv 
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CFcLpLCLTOs hidcrracns hi(f)vr)s piev ovoa, rrpos /xtav he 

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epurpoadev Kal omcrOev, to Se Se^tov Kal dpiorepov 
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etvat 7racrt Kal rwv alaO^rrjpLcov e/caorov. Kara 
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to [jLev {jitet^ov} 2 ets ra Sefta, to 8' e'Xarrov els rd- 

piorepa ftovXerai rr)v 0eoiv e^etv. ov fJirjv dXXd Kal 

iv rots cporoKocs rjrrov fiev rj irrl rovrwv cjiavepov, 

iviOLS he \_KaKet djGTrep ev Ttat] 3 ^wotokocs eVtS^AaJS 1 

hiearrjKev, otov Kara nvas rorrovs ot SaowoSe? Suo 

1 ye Peck : vulg. 2 jietlov conieceram ; maiorpars 2. 
3 seclusi : cbcnrep €v rim om. EY : kolkcIvcov coni. Th. 



the possession of a lung is one of their essential 
characteristics, just as there are certain char- 
acteristics which are included in the essence of 
a " bird," the name which is applied to another such 

VII. Some of the viscera appear to be single why the 
(e.g. the heart and the lung) ; others double ^double. 
(e.g. the kidneys) ; and some it is difficult to place 
under either heading. The liver and the spleen ap- 
parently are intermediate ; they can be considered 
either as each being a single organ, or else as two 
organs taking the place of one and having a similar 
character. In fact, however, all of them are double. 
And the reason for this is that the structure of the 
body is double, though its halves are combined under 
one source. We have upper and lower halves, front 
and back halves, right and left halves. Thus even the 
brain as well as each of the sense-organs tends in all 
animals to be double ; so does the heart — it has 
cavities. In the Ovipara the lung is so much divided 
that they appear to have two lungs. The kidneys 
are obviously double ; but there is fair room for 
hesitation about the liver and spleen. This is be- Liver and 
cause in those animals which of necessity have a s P leen - 
spleen, the spleen looks rather like a bastard liver, 
while in those which have a spleen though not of 
necessity — i.e. a very small one, as it were by way 
of a token — the liver is patently double, and the 
larger part of it tends to lie towards the right, the 
smaller towards the left. Still, there are cases even 
among the Ovipara where this division is less distinct 
than in those just described, while in some Vivipara 
the division is unmistakable — e.g. in some districts 



35 ookovgiv rpraT £X eiv > K ^drrep Twv lyBvcov errepol 
ri Tives Kal ol GeXax^oecs. 
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fjL&XAov r) tov gtt\t}v6s yeyove (f>VGis, wgt dvay- 
kollov jiev rrws, pr) Xlav §' elvai Tract tols Repots* 

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1 /ecu KaOdnep PZ : /cat om. vulg. 



hares appear to have a couple of livers ; so do certain 
fishes, especially the cartilaginous ones. a 

The spleen owes its existence to the liver being 
placed somewhat over to the right-hand side of the 
body : this makes the spleen a necessity in a way, 
though not an urgent one, for all animals. 

Thus, the reason why the viscera are double in 
their formation is, as we have said, that the body 
is two-sided, having right and left. Each of the two 
aims at similarity, just as the sides themselves strive 
to have a similar nature, and to be as like as twins ; 
and just as the sides, though dual, are conjoined 
together into a unity, so also it is with the several 

The viscera which are below the diaphragm are 
all of them present for the sake of the blood-vessels, 
in order that the latter may have freedom of carriage 
and at the same time be attached to the body by 
means of the viscera, which act as a bond. Indeed, 
there are, as it were, anchor-lines thrown out to 
the body through the extended parts : e.g. from the 
Great Blood-vessel to the liver and to the spleen, for 
these viscera act, as it were, like rivets and fasten it 
to the body ; that is to say, the liver and the spleen 
fasten the Great Blood-vessel to the sides of the body 
(since blood-vessels pass to them from it alone), while 
the kidneys fasten it to the rear parts. And to the 
kidneys — to each of them — there is a blood-vessel 
passing not only from the Great Blood-vessel but 
also from the Aorta. 

These advantages, then, accrue to the animal organ- 
ism from the lower viscera. Liver and spleen also 
assist in the concoction of the food, since they both 

"° Sharks, etc. 


[jirjv e^et rrjv (f>vaiv) t ot $e v€<f>pol Trpos to Trepvr- 


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1 raGra P : Taura \16vov vulg. 

2 rrXrjprjs EYZ : irXypT} vulg. 

3 <oucm> Peck. 



have blood in them and so are hot. The kidneys 
assist in connexion with the residue which is excreted 
into the bladder. 

Now the heart and the liver are necessary to all 
animals. The heart is necessary because there must 
be a source of heat : there must be, as it were, a 
hearth, where that which kindles the whole organism 
shall reside ; and this part must be well guarded, 
being as it were the citadel of the body. The liver is 
necessary for the sake of effecting concoction. All 
blooded creatures must have these two viscera, and 
that is why these two are always present in them. 
A third, the lung, is present in those animals that 

But the spleen, where present, is present of necessity spleen, 
in the sense of being an incidental concomitant, as 
are the residues in the stomach and in the bladder. 
So in some animals the spleen is deficient in size, 
as in certain birds which have a hot stomach, e.g, 
the pigeon, the hawk, and the kite ; the same applies 
to the oviparous quadrupeds (all of these have an 
extremely small spleen) and to many of the scaly 
creatures. These animals just mentioned also lack 
a bladder, because their flesh is porous enough to 
enable the residues formed to pass through it and 
produce feathers and scales. For the spleen draws 
off the residual humours from the stomach and in 
virtue of its blood-like nature can assist in the con- 
coction of them. If, however, the residue is too 
bulky or the spleen has too little heat, the stomach 
gets full of nourishment and becomes diseased. 
And in many cases, when the spleen is ailing, 
the stomach becomes hardened owing to the 
fluid which runs back into it. This happens with 



ras vypoT7)Tas. ols oe oXlyrj TTeplrrcoats ylverai, 
KaOdwep tois opveois Kal tols IxOvgl, ra fiev ov 
fiiyav e^et, ra Se GrjfjieLOV x^P tv - KaL €>v T0 ^ 


ve<j)pu)8r)s 6 gttXtjv eon hid to tov irXevpLOva GOfi<f)dv 

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C0O7T€p €tS TO. TTTepd TOls OpVLGLV . 

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evaifAOV vypos eari hid re ttjv elprjfievrjv alriav Kal 
Sta to rrjv (j>VGiv ttjv TO)v dpLGTepcov oXcos vypo- 
20 repav elvai Kal ijjvxporepav. oirjprjrai yap rebv 
evavrliov et<aarov TTpos r-qv uvyyevrj avcrrotxtav, 
olov oe^tov evavrlov dpLarepa) Kal Oepfiov evavrlov 
i/wxptp' Kal uvuroix a ydp d)\XrjXoLS elal tov elprj- 
fievov rpoirov. 

. 01 oe ve<f>po\ rots e^ouatv ovk e£ dvdyKrjs aAAa 

tov ed Kal KaXws eveKev virdpxovGiv rrjs yap 
25 TTepiTTwcrecos X^P lv € ^ T V y kvgtlv ddpoL^opLev-qs 

etcrt Kara ttjv lolav <j)voiv, ev ogols TrXeiov vtto- 

GT7)i±a ylverai to tolovtov } ottojs fieXriov airooiotp 

7] kvgtls to avrrjs epyov. 

'Knee oe rrjs avrrjs eveKa ^peaxs rovs Te ve<j>povs 

GVufiefirjKev ex^tv ra £aia Kal ttjv kvgtlv, XeKreov 
so Trepl KVGrews vvv } virepfidvras tov e<f>e£fjs tqjv 

fioplajv dpiOfiov irepl yap <f>peva>v ovBev ttw Si- 

° The reference to the " columns " or " double list " is 
not clear. There was a Pythagorean gvotolx^ ; this and 
other ovoroixlai are mentioned in Ross's note on his trans- 
lation of Met. 9S6 a 23. 

b i.e. left and cold are both in the same column ; right and 
hot are both in the other column. 


those who make water excessively : the fluids are 
drawn back again into the stomach. But in animals 
where the amount of residue produced is small, as in 
birds and fishes, the spleen is either small or present 
simply by way of a token. In the oviparous quadru- 
peds, too, the spleen is small and compact, and 
like a kidney, because the lung is spongy and the 
animals drink little, and also because the residue 
which is produced is applied for the benefit of the 
body itself and of the scaly plates which cover it, 
just as in birds it is applied for the benefit of the 

In those animals, however, which possess a bladder, 
and whose lung contains blood, the spleen is watery. 
The reason already given partly explains this. An- 
other is that the left side of the body is generally 
more watery and colder than the right. As we know, 
the opposites are divided up into two columns,® so 
that each is classed with those that are akin to it, e.g. 
right is in the opposite column to left, and hot to 
cold ; and thus some of them stand together in the 
same column, as I have just indicated. & 

Kidneys are present in some animals, but not 
of necessity ; they are present to serve a good pur- 
pose ; that is to say, their particular nature enables 
them to cope with the residue which collects in the 
bladder, in those cases where this deposit is somewhat 
abundant, and to help the bladder to perform its 
function better. 

Since the bladder is present in animals to serve 
precisely the same purpose as the kidneys, we must 
now say something about it. This will involve a 
departure from the serial order in which the parts 
actually come, for we have said nothing so far about 



670b / ~ »/ * * >' 

wpiorai, tovto be tl tojv irepi ra oirAayxya fiopicov 

ear iv, 

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Std yap rrjv i>7T€po)(rjv rrjs (jzvaews, rjv e\ovatv iv 
tco fioplto Tovroj, Sii/jrjTiKd T€ tclvt earl /xaAtcrra 
to)v ^tocov, /cat SetTat Tpo<f)r)s ov \iovov rrjs £rjpas 
dXXd koI Trjs vypds TrXeiovos, tScrr' i£ dvayKTjs /cat 
1 6 77€ptrTa>/xa yivzodai irXelov /cat ^ togovtov (jlovov 

OGOV V7TO Trjs KOlXlCLS 7T€TT€g9(1L /Cat €KKp[v€G0OLL 

OL07T€p oaa 7rAeu/xova e^et tolovtov, diravT* e^et 
kvgtiv ogol Se jit^ toiovtov, dAA' 7} dAtyd7roTa eort 
10 Std to 7rAei>/zova e^et^ GOfx<j)6v, r] oXcos to vypov 

77 pOG(j)€p€TaL OV 7TOTOV X^P LV dAAd TpO(f>fj$, OLOV T(X 

evTopia /cat ot IxOvzs, eVt Se 77TepaJTa e'artv 7) 
AeTrtSojrd ?} (/>oAt8cuTa, raura 8t' dAtydr^Ta re T7j? 
to£> vypov 7TpoG<f>opas /cat Std to TpeVeaflat et? 
ravra to 7reptytvd/zevov tol> TTepiTTcopLarog ovSev 

15 ^X et ^o^ TtiJ,/ kvgtiv, ttXtjv at ^eAcDvat Tttiy </>oAtSaj- 
Taiv, /cat ivTavO' rj c^vgls KeKoXoficorai [xovov avriov 
8* OTt at /xev 0aAaTTtat GapKtoSrj /cat evaifiov e^ouat 
tov irXevfjiova /cat ofioiov rep fioelco, at Se ^epaatat 
fiei^co r] Kara Adyoy. ert Se Std to oGrpaKOJoes 

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vypov Std fjiavdjv twv oapKcbv, olov tois opviGt /cat 

TOtS 1 0(j)€Gl KCU TOl$ dX\oi$ TOL$ </>oAtSoJTOtS, UTTO- 



the diaphragm, though this is one of the parts that 
are near the viscera. 

VIII. The bladder is not present in all animals : Bladder. 
Nature seems to have intended only those animals 
which have blood in their lung to have a bladder. 
And this is quite reasonable, when we remember that 
such animals have an excess of the natural substance 
which constitutes the lung, and are therefore more 
subject to thirst than any others ; i.e. they need a 
larger amount of fluid food as well as of the ordinary 
solid food, and the necessary result of this is that a 
larger amount of residue also is produced, too large 
in fact for all of it to be concocted by the stomach 
and excreted with its own proper residue ; hence it 
is necessary to have some part that will receive this 
additional residue. This shows us why all animals 
which have blood in their lung possess a bladder 
too. As for those whose lung is spongy and which 
therefore drink little, or which take fluids not as 
something to drink but as food (e.g. insects and 
fishes), or which are covered with feathers or scales 
or scaly plates, not one of these has a bladder, owing 
to the small amount of fluid which they take and 
owing to the fact that the surplus residue goes 
to form feathers or scales or scaly plates, as the 
particular case may be. Exceptions to this are the 
Tortoises : though scaly-plated they have a bladder. 
In them the natural formation has simply been 
stunted. The cause of this is that in the sea-varieties 
the lung is fleshy and contains blood, and is similar to 
the lung of the ox ; while in the land-varieties it is 
disproportionately large. And whereas in birds and 
snakes and the other scaly-plated creatures the 
moisture exhales through the porous flesh, in these it 



671 a 

araois yiverai roaavrrj ware hetadai rrjv <j>vaiv 
avrtbv k'xeiv ri [lopiov heKrtKov Kal dyyeiwhes. 


•25 ravrrjv rrjv air lav 3 rj jxev daXarrla jxeydXrjv, at he 
Xepoalai piiKpdv -ndjiTrav. 

IX. ^Ojiolws 8' e^et Kal rrepl vecfipoov. ouSe yap 
vecppoijs ovre rcov rrrepcorcov Kal XeTUOcorcov ovhev 
e'xei ovre rcov (/xdAlScvtcov, ttXtjv al OaXdrriai 
XeXwvcLL heal al ^epcrcuar dXX cos rfjs ei? rovs 

so ve<f>povs rerayjievrjs oapKos ovk exovarjs )(a>pav 
dXXa hieairappLevrjs els iroXXd, irXarea vecbpoechfj ev 
evlois rcov opvlOcov ear iv. fj 8' ejivs ovre kvgtlv 
ovre vechpovs e'x et * Sid rrjv jxaXaKorrjra yap rod 
XeXcovLOV evoidirvovv yiverai ro vypov. f) jiev ovv 
ejxvs Sid ravrrjv rrjv alrlav ovk e^ei rcov jxoplcov 
ovherepov rots S' aXXoig ^cools rots eyovoiv ev- 

35 aifiov, warrep elprjrai f rbv nXevjiova rraot cvp,- 
e7ib^€^r)Kev ex^w ve(f>povs. Karaxprjrai yap fj chvois 
djia rcov re tfiXeficov %dpiv Ka ^ ^rpos rrjv rov 
vypov Trepirrcofiaros eKKpiaiv tpepei yap els 
avrovs nopos eK rfjs jxeydXrjs tpXefios* 
"E^oucri 8' ol ve<f>poi rrdvres kolXov, r) rrXetov fj 
5 eXarrov, ttXtjv ol rfjs <j>cl)Krjs' ovroi 8' ojjlolol rots 
fioelois ovres orepecbrarot ndvrcov elolv. ojxoloi he 
Kal ol rov dvdpcorrov rots fioelois* elol yap coorrep 
ovyKeljxevoi eK rroXAcov vetf>pcdv yuKptov Kal ovx 
SfxaXets, coairep ol rcov rrpo^drcov Kal rcov dXXcov 
rcov rerpaTrohcov. Sio Kal ro dppcourrjyLa rots 

° Greek, " hemys." This description, which does not fit 


cannot do so, because the integument which surrounds 
them is dense, like a shell ; and so the excretion is 
produced in such quantities that the Tortoises need 
some part which shall act as a vessel to receive it. 
That, then, is why they are the only animals of the 
kind which have a bladder. In the sea-tortoise it is 
large, in the land-tortoise quite small. 

IX. Much the same may be said of the kidneys as Kidneys, 
of the bladder. Kidneys are not present in any of 
the animals that have feathers or scales or scaly plates, 
except the two sorts of tortoises just mentioned. In 
some birds, however, there arc flat kidney-shaped 
objects, as if the flesh that was allotted to form the 
kidneys had found no room for its proper function 
and had been scattered to form several organs. The 
Emys a has neither bladder nor kidneys : this is be- 
cause it has a soft shell which allows the moisture to 
transpire freely through it. But, as I said before, all 
the other animals whose lung contains blood have 
kidneys, since Nature makes use of them for two pur- 
poses : (1) to subserve the blood-vessels ; and (2) to 
excrete the fluid residue. (A channel leads into them 
from the Great Blood-vessel.) 

There is always a hollow (lumen), varying in size, 
in the kidneys, except in the seal, whose kidneys are 
more solid than any others and in shape resemble 
those of the ox. Human kidneys too resemble those 
of the ox : they are, as it were, made up out of a 
number of small kidneys, b and have not an even 
surface like those of the sheep and other quadrupeds. 
Thus, when once an ailment attacks the human 

any animal now known as Emys, seems to be that of some 
freshwater tortoise. 

b This is not true of the normal adult, but it is true of 
the foetus. 



10 dvdpcorroLs SvaairdWaKTov avTwv Igtiv, av anag 
voGrjaajcrw cru/xjSatVet yap WGirep ttoXXovs ve<j>povs 
vogovvtwv ^aAeTTturepav etvai rrjv taaiv rj twv eva 


*0 S' GLTTO TTjS <f)Xefi6s T€LVWV TTOpOS OVK €1$ TO 

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15 avTwv ovk iyylvercu atfia, ovoe ir-qyvvrai TeXev- 
rd)vra>v t e/c Se tov kolXov twv ve<f>pwv <f>epovGi 
TTopoi avat/xot els rrjv kvgtlv ovo veaviKol, i£ 
eKarepov els, /cat aAAot e/c tt)s doprrjs ta^upot /cat 
avvexeZs. ravra S' e^ei tov rporrov tovtov onws 
e.K fiev rrjs <f>Xef3d$ to TrepiTTwy^a Trjs vypoT7]Tos 

20 jSaSifj? els tovs ve(f>povs, eK oe twv ve<f>pwv 7) 


tov GwpiaTOS twv ve<j)pwv els to fieGOV Gvpperj, ov 
to koiXov ot TrXeiGTOi eypVGiv avTwv (816 Kal ovo- 
cooeGTdTOV tovto tojv GirXdyxywv IgtLv\ eK oe tov 
yLe.Gov Sid tovtwv twv iropwv els TTjV kvgtlv rjo-q 
25 pidXXov ws TrepiTTWpia aTTOKplveTai . KaQwppiGTai 

eiprjTCLl, TTOpOL LGXVpOl 7Tp6$ aVTTjV, 

01 p.ev ovv V€(f>pol Sta TaJra? to,? atrtas 1 etat, Kal 
Tas SwdpLCis exovGi Tas elprjpievas. 

'Ev TT&Gi oe tols e^ovGL ve<f>povs 6 oetjios dvwTepw 
tov dpLGTepov Igtlv oid ydp to tt\v klvt]glv elvai 
so Ik twv Seftcuv /cat loyypOTepav Sta TavT elvai Trjv 


• The ureters. 


kidneys, the trouble is not easily removed, because 
it is as though the patient had many kidneys diseased 
and not one only ; and so the cure is more difficult to 

The channel which runs from the Great Blood- 
vessel to the kidneys does not debouch into the 
hollow part of the kidneys, but the whole of what 
it supplies is spent upon the body of the kidneys ; 
thus no blood goes into the hollows, and at death 
none congeals there. From the hollow part of the 
kidneys two sturdy channels a lead into the bladder, 
one from each ; these contain no blood. Other 
channels come from the Aorta to the kidneys ; 
these are strong, continuous ones. This arrange- 
ment is on purpose to enable the residue from the 
moisture to pass out of the blood-vessel into the 
kidneys, and so that when the fluid percolates 
through the body of the kidneys the excretion that 
results may collect into the middle of the kidneys, 
where the hollow is in most cases. (This explains, 
incidentally, why the kidney is the most ill-scented 
of all the viscera.) From the middle of the kidney 
the fluid is passed off through the aforesaid channels 
into the bladder ; by which time it has practically 
taken on the character of excremental residue. The 
bladder is actually moored to the kidneys : as has 
been stated, there are strong channels extending 
from them to it. 

We have now given the causes for which the 
kidneys exist, as well as their character and functions. 

The right kidney is always higher up than the left. 
The reason for this is that as motion always begins on 
the right-hand side, the parts that are on that side are 
stronger than those on the other ; and owing to this 




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35 Sid to dv€G7rda9ai dvwTepov tov Se^iov v€<f>pov to 
' rjirap a7TT€Tai tov oe^iov v€<j>pov iv rraoiv iv tols 
672 a de^ioTs yap to rjTrap. 

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TTLfJLeXrjv, i£ dvdyKTjs fiev Sid to SaqdeiGdat to 
rrepiTTwyia Sid Ttbv vecfrpwv to yap Xenrofxevov 
atfia KaBapov ov €V7T€tttov ioTi, TeXog 8* evTreifjlas 
5 alfjLaTiKrjs 7TLfi€Xrj Kal GTeap ioTiv. (d!)07T<zp yap iv 
to is TreirvpwpLivois i;y)pois } olov tt) T€(f>pa t ey/cara- 
AetVerat rt Txvp y ovtoj Kal iv tols 7T€7T€fifi€V0LS 
vypois • iyKaTaXeiTTCTai yap tl TTjs elpyaofievrjs 


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Sia(f>opd tovtcov eiprjTai irpoTepov iv €T€poi$. 

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V CO TOV GapKO)o4s ioTlV, 07760? fj 7Tpoj3oXrj TOtS 7T€pL 
1 raura Peck : Travra vulg. 


a See Book II. ch. v. 


motion they are bound to make their way upwards 
before the ones on the left. Thus people raise the 
right eyebrow more than the left, and it is more 
arched. A result of this drawing up of the right 
kidney is that in all animals the liver, which is on the 
right side of the body, is in contact with it. 

The kidneys contain more fat than any other of the Fat in 
viscera. This is partly a necessary consequence upon kldne y 9 - 
the percolation of the residue through the kidneys : 
in other words, the blood which gets left behind there 
is easy of concoction because it is pure, and when 
blood undergoes complete concoction the final pro- 
ducts are lard and suet. (A parallel is to be found in 
the case of solid substances which have undergone 
combustion : e.g. a certain amount of fire gets left 
behind in ash. So, in fluid substances which have 
undergone concoction : some portion of the heat 
which has been generated remains behind. That is 
why oily substances are light and come to the top of 
fluids.) This fat is not formed actually in the kidneys 
themselves, because they are so dense : it collects 
outside them. In some it has the form of lard, in 
others the form of suet, according to the character of 
the animal. (The difference between the two has 
been explained already in another connexion.) 

This formation of lard, then, about the kidneys is 
the necessary consequence upon the conditions which 
necessarily obtain in animals that possess kidneys. 
But there is another reason for its formation, and that 
is, on purpose to safeguard the kidneys themselves 
and to preserve their natural heat. The kidneys are 
the outermost of all the viscera, and therefore they 
need more warmth. Whereas the back is liberally 
supplied with flesh, which enables it to act as a 



672 a 

rrjv Kaphlav GTrXayxvois , rj 8' 0G(f)vs aoapKos 
(aoapKoc yap ai KapLTral ttolvtcqv)- glvtl aapKOS ovv 
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TTtoves ovtcs' to yap Xirrapov deppbov, tt€TT€l S' r) 


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ivavria' tt}K€L yap to ttlov pL&XXov. 

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V€(f>povs £X €LV KLovas, Kal ttoXXolkls eypvoiv SXovs 
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30 iXXeiTrei Ti y av pcrj Arar' dpL^OTepovs, dXXa /cara tov 
Be^Lov. 1 aiTiov Bk tov puovov rj ^xaAtara tovto 

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fidXXei* yiWrai ydp rreplve^pa ra^iora twv t^cowv 
ra rrpofiaTa rrdvTWV. iyKaTaKXeiopLevrjs ovv Trj$ 
vypoTTjTos Kal twv TTvevpLaTcov Bid tov GcfraKcXiGpidv 

1 aAA* av . ♦ . Bcgiov post elolv 1. 23 transponit Thurot. 


protection for the viscera about the heart, the loin, 
in common with all parts that bend, is not so supplied ; 
and this fat we have been speaking of serves as a 
safeguard to the kidneys in place of flesh. Further, 
the kidneys are better able to secrete and to concoct 
the fluid if they are fat, because fat is hot and heat 
causes concoction. 

These are the reasons why the kidneys are fat. In 
all animals, however, the right kidney has less fat 
than the left. This is because the right-hand side 
is dry and solid and more adapted for motion than 
the left ; and motion is an enemy to fat, because it 
tends to melt it. 

Now it is an advantage to all animals to have fat 
kidneys, and often they are completely filled with fat. 
The sheep is an exception : if this happens to a sheep 
it dies. But even if the kidneys are as fat as can be, 
there is always some portion which is clear of fat, if 
not in both kidneys, at any rate in the right one. The 
reason why this happens solely (or more especially) 
to sheep is as follows. Some animals have their fat 
in the form of lard, which is fluid, and thus the wind 
cannot so easily get shut up within and cause trouble. 
When this happens, however, it causes rot. Thus, too, 
in the case of human beings who suffer from their 
kidneys, although it is an advantage for them to be 
fat, yet if they become unduly fat, pains result which 
prove fatal. As for the animals whose fat is in the 
form of suet, none has such dense suet as the sheep 
has ; and moreover, in the sheep the amount of it is 
much greater ; the fact that they get fat about the 
kidneys much more quickly than any other animal 
shows this. So when the moisture and the wind get 
shut up within, rot is produced, which rapidly kills 



672 b 

5 dvaipovvrai rax^S' Sid yap rrjs doprrjs kcu rrjs 
(frXefSds ev9vs drravra rd rrdOos rrpds rrjv KapSiav 
ol Se rropoi avvexeis drrd rovrajv twv <j>Xej3a>v elac 


Ylepl p.ev ovv rrjs KapSlas Kal rrXevfiovos eiprjrai, 
Kal rrepl rjrraros Kal crrrXrjvds Kal vej>p<x)v. X. rvy- 

10 yav£i Se ravra K€yu>pio\iiva aAA^Acuv ra> Sia£a>- 
fian. rovro Se to Std^wjia kclAovol rives <f>pevas m 
o Siopl^ei rov re rrXevpiova Kal rrjv KapSiav. KaXelrai 
Se rovro rd Std^wfia ev rots evaifiois, a)crrrep Kal 
eiprjrai 3 <f>peves. ex^i Se rrdvra rd eWi/xa avrd, 
KaOdrrep KapSiav Kal rjrrap, rovrov 8' alriov on 

is rov SiopiopLOv X^P LV ^orl rod re rrepl rrjv KoiXlav 
rorrov Kal rov rrepl rrjv KapSiav, orrajs r) rrjs 
alaOrjrLKrjs *P V XV$ ^PXV drradrjs rj Kal fir) ra^i 
KaraXanfidvYjrai hid rrjv drrd rrjs rpo(f>ijs yivofievrjv 
avadvpLiaoiv Kal rd rrXrjdos rrjs erreiaaKrov 6ep- 
fiorrjros- errl yap rovro SieXafiev r) <j>vois, otov 

20 TrapoLKoSofirjiJia rroirjaacra Kal (frpaypidv rds (f>pevas } 
Kal SieiXe ro re rtpLiajrepov Kal rd drifiorepov ev 
doois evSex^rac SieXeiv rd dva> Kal Karw rd piev 
yap dva> earlv ov eveKev Kal fieXriov, rd he Kara) 
rd rovrov eveKev Kal avayKalov , rd rrjs rpo<f>rjs 

"Eotl Se rd Sid^wfia rrpds fiev rds rrXevpds 
25 aapKO)Searepov Kal la)(vp6repov, Kara fiecrov 8' 
vfievwSearepov' ovra> yap rrpds rrjv ic?x vv Kal rrjv 
rdoiv xprjCFifiwrepov. Sidri Se rrpds rr)v Oepfidrrjra 
rrjv KarojOev otov rrapajyvdSes elal, crrjfietov 4k ra>v 


the sheep off. The disease makes its way directly to 
the heart through the Aorta and the Great Blood- 
vessel, since there are continuous passages leading 
from these to the kidneys. 

We have now spoken of the heart and the lung ; 
and also of the liver, the spleen and the kidneys. 
X. These two sets of viscera are separated from Diaphragm, 
each other by the diazoma, which some call the 
pkrenes (diaphragm). This divides off the heart and 
the lung. In blooded animals it is called pkrenes, as 
I have said. All blooded creatures have one, just as 
they all have heart and liver. The reason for this 
is that the diaphragm serves to divide the part 
round the stomach from the part round the heart, 
to ensure that the source of the sensory Soul may be 
unaffected, and not be quickly overwhelmed by the 
exhalation that comes up from the food when it is 
eaten and by the amount of heat introduced into the 
system. For this purpose, then, Nature made the 
division, and constructed the pkrenes to be, as it were, 
a partition-wall and a fence ; and thus, in those 
creatures where it is possible to divide the upper 
from the lower, she divided off the nobler parts 
from the less noble ones ; for it is the upper which 
is " better," that for the sake of which the lower ex- 
ists, while the lower is *' necessary," existing for the 
sake of the upper, by acting as a receptacle for the 

Towards the ribs the diaphragm is fleshier and 
stronger, -while in the middle it is more like a mem- 
brane : this makes it more serviceable as regards 
strength and extensibility. An indication to show 
why there are, as it were, " suckers," to keep off the 
heat which comes up from below, is provided by 



672 b 

crvfifiaLVovTOJV Srav yap Sta rrjp yeirvlaaiv cXkv- 
GOioiv vypdrryra Oepfirjv /cat irepiTTCofjLaTLKrjv, ev9vs 
so iTn$r)Aa)s rapdrrei rrjv Sidvoiav /cat rrjv accrBrjoLv, 
Sto /cat kclAovvtcli <fypeves chs fJL€T€xovcrat ri rod 
<f>poveiv. at he fierexovuL fiev ovhev, eyyvs 8* 


fioXrjv rrjs Stavotas*. Sto /cat Xe7Tral /card fiecrov 
elcrlv, ov fiovov i£ dvdyKrjs, ore aapKcboets ovaas rd 

35 TTpOS TOLS TrXevpds dvayKOLLOV €LVOU OapKOiheGTepaS 

dAA' tv on oAiyiGTrjs ixerex^oiv t/c/xaSos" aapKO)- 

673 a Set? yap dv ovuac /cat et^ov /cat elXKov fiaXXov 

t/c^taSa 7toAAt)V. oti he depfiaivofxevai Ta^e'cos* 
€ir[h7}Aov ttolovgl rrjv alaOrjaiv, ar\\ialvei /cat to 
rrepl rovs yeXwras avfifiacvov yapyaXi^dfievoi re 
yap ra^y yeXcocri, Std to rrjv Kivrjcriv d(f)LKve tad at 

6 raxv rrpos tov tottov tovtov, depfiaivojievov 1 §' 
rjpdfxa rroceiv ofia)s erTiS^Xov /cat Kiveiv rrjv Sta- 
voiav rrapd rrjv rrpoaipecriv. tov ok yapyaXt^eaOai 
fiovov dvOpcorrov airiov -q re Xe7rr6rr]$ rod hepfiaros 
/cat to fiovov yeXdv tqjv £aja)V dvOpwrrov. 6 oe 
yapyaXiafios yeXoJS earl hid Kcvrjaecos 2 roiavrrjs 

10 rod fioplov rod rrepl rrjv fiaaxdXrjv. 

HvfifiacveLV oe (f>aoi /cat rrepl rd$ ev rots rroXefiois 
rrXr]yds ets* tov tottov tov rrepl rds <f>peva$ yeXwra 
Sta rrjv ei< rrjs rrXrjyrjs ytvofievrfv depfiorrjra* tovto 

1 8epfiaiv6fj.€vov Peck : Oepfiaivovoi vulg 1 . : -ovaa SZ : -ovaav 
PUY. 2 /cn}a€co? Langkavel. 

° The Risus Sardonicus : see Allbutt and Rolleston, A 
System of Medicine 2 (1910), viii. 642. 



what actually happens : whenever, owing to their 
proximity, they draw up the hot residual fluid, this 
at once causes a recognizable disturbance of the 
intelligence and of sensation. And that is why they 
are called phrenes : as if they took a part in the act 
of thinking (pkronein). This of course they do not 
do ; but their proximity to those organs which do 
so take part makes the change of condition in the 
intelligence recognizable. That, too, is why the 
phrenes are thin in the middle ; this is not due 
entirely to necessity (though as they are fleshy to 
begin with, the parts of them nearest the ribs must 
of necessity be more fleshy still) ; there is another 
reason, which is, to enable them to have as little 
moisture in them as possible, since if they had been 
wholly of flesh they would have tended to draw 
to themselves and to retain a large quantity of 
moisture. Another indication that it is when heated 
that they quickly make the sensation recognizable is 
afforded by what happens when we laugh. When 
people are tickled, they quickly burst into laughter, 
and this is because the motion quickly penetrates to 
this part, and even though it is only gently warmed, 
still it produces a movement (independently of the 
will) in the intelligence which is recognizable. The 
fact that human beings only are susceptible to 
tickling is due (1) to the fineness of their skin and 
(2) to their being the only creatures that laugh. Tick- 
ling means, simply, laughter produced in the way I 
have described by a movement applied to the part 
around the armpit. 

It is said that when in war men are struck in the 
part around the diaphragm, they laugh a on ac- 
count of the heat which arises owing to the blow. 



\ a ^ 
yap fiaXXov eonv dtjcoTTLorajv aKovoai Xeyovrwv rj 
to irepl rrjv KecfraXrjV, d>$ aTTOKOTreloa <f)8eyyerai 

is r&v dvOpcbrrwv. Xeyovoi yap rives eirayopievoi Kai 
rov "OpLrjpov, ws oca rovro Troirjoavros 

<§>§eyyo\iivr\ 8' dpa rov ye Kapr) Kovlrjcnv 

aAA' ov cf>6eyyopevov. irepl he ^ApKahlav 1 ovrw 

TO TOLOVTOV 8l€7TlOTeVOaV WGTe Kai KpLOLV e-noir\- 

oavro irepl tlvos rcov iy)(copLwv. rov yap cepetos 
20 rov oirXocrfJLcov Ato? drrodavovros y v(j) orov he dhrj- 
Xov OVTOS, 2 ecf>aadv rives aKovoai rrjs Ke<f>aXrjs 
aTTOKeKOfjLfJLevrjs Xeyovorjs 7toXAolkl$ 

err* dvhpos dvhpa VLepKihas direKreivev 
hid Kai tpqrrjuavres & dvofia rjv ev ra> roircp 
VLepKihas, eKpivav. dhvvarov he (j>deyyeu9ai /ce^cu- 
pLGfxivqs rrjs dprrjplas Kai avev rrjs eK rov uXev- 
25 p,ovo$ KivTjoecos. TTapd re rots fiapfidpois y Trap 
ots dirorepivovai ra^ojs rds Kec^aXds, ovhev ira> 
roiovrov GVfiPe^rjKev, en S' eirl rwv aAAaw £,cpa)v 
Sid rlv air Lav ov yiverai; [to jjiev yap rov yeXoj- 
ros irXrjyeiodjv rcov tbpevtov eiKortos, ovhev yap yeXa 
rwv dXXcov TTpo'Cevai he ttol to Utopia rrjs Kec/>aXrjs 
so dcprjpr)p.evr}S ovhev aXoyov, eirel rd y dvaipa Kai 

1 apxahlav Z, probat J. Schaefer de Jove apud Cares culto, 
pp. 370 sq. : Kaplav vulg. : xap . . av E : Kap P. 

2 Se db-qXov ovtqs Peck : hk Brj aSrjXtos vulg. : codd. varia. 

° Iliad, x. 457 and Od, xxii. 329. In both places the 
text of Homer has ^deyyoixevov (" As he spake . . ."). 

b The Berlin text here reads " Caria," but the Oxford ms. 
Z reads " Arcadia." A cult of Zeus hoplosmios is attested 
only for Methydrion, a town in Arcadia, and the name 
Kerkidas is found in Arcadia, not in Caria. (See A. B- 


This may be so ; and those who assert it are more 
credible than those who tell the tale of how a man's 
head speaks after it is cut off. Sometimes they cite 
Homer in support, who (so they say) was referring to 
this when he wrote 

As it spake, his head was mingled with the dust 


As he spake, his head was mingled with the dust.) a 
In Arcadia 5 this kind of thing was at one time so 
firmly believed that one of the inhabitants was 
actually brought into court on the strength of it. 
The priest of Zeus hoplosmios had been killed, but 
no one knew who had done it. Certain persons, 
however, affirmed that they had heard the man's 
head, after it had been cut off, repeating the follow- 
ing line several times 

'Twas Kerkidas did slaughter man on man. 
So they set to work and found someone in the 
district who bore this name and brought him to trial. 
Of course, speech is impossible once the windpipe 
has been severed and no motion is forthcoming from 
the lung. And among the barbarians, where they 
cut heads off with expedition, nothing of this sort 
has taken place so far. Besides, why does it not 
occur with the other animals ? [For (a) the story 
about the laughter when the diaphragm has been 
struck is plausible, for none of the others laughs ; 
and (b) that the body should go forward some distance 
after the head has been cut off, is not at all absurd, 
since bloodless animals at any rate actually go on 

Cook, Zeus, ii. 290, who gives the evidence, and J. Schaefer, 
De Jove apud Cares culto, 1912, pp. 3T0 f.) 




673 a 

£77 ttoXvv xpovov SeS^Acorat hk nepl rr\s aiTias 
avTcdv iv irepois.'] 1 


yycov } etp^rai* yiyove 8' e| avdyKrjs iirl rots' ivros 
iripaai tcov ^Xeficov, i^Uvai t€ yap tK/xaSa avay- 
673 b kcllov, Kal ravrrjv alfxarcK-qVy i£ rjs aWLarafxevrjs 
Kal TTTjyvvfJLevrjs ytveoOai to Utopia tcov OTrXdyxycov 
SioTrep at/xartKa, Kal avTOts fxev ofioiav ex oV(Jt TT i v 
rod otbfjiaTos <f)v<jiv } tols 8' aAAots 1 avopLOtav. 

XI. ITa^ra Se ra tnrXdyxya iv vfievi ioTiv 
6 TrpofioArjs T€ yap Set Trpos to a7Ta6rj elvai, Kal 

TavTTjs iXa<j>pas, 6 8' vfxrjv ttjv <j>v&LV toiovtos' 

7TVKVOS fJL€V yap LOOT 0L7T0OT€y€LV , auapKOS Se LOOT€ 

pur) zXkciv /-177S' (ix €tv iKpidha, Xztttos 8' ottcos kov- 

<f>0$ fj Kal pL7]$€V TTOlfj fidpOS . {liyitTTOl Se Kal 

Icr^vpoTaToi tcov vfiivcov elalv 01 re 7T€pl tt]v 
10 Kaphlav Kal irepl tov iyK€<f>aXov t evXoycos* Tavra 
yap Setrat TrXe'iUTrjs <f>vXaKrjs m rj p,kv yap (j>vXaK7j 
TTepl tol Kvpia, TavTa Se Kvpia /zaAtara ttjs ^coijs. 

XII. "E^oucrt 8' evia [xev tcov l^cocov iravTa tov 
apiBfiov avTtov, evia 8' ov irdvTa' 77-ota Se raura Kal 
Sta tLv aiTiav, eiprjTai rrpoTepov. Kal tcov iypvTCOv 

15 Se TavTa hiatbipovoiv ov yap opcoias ovt€ ra? 
KapSiag €)(ovcn TrdvTa to. e^ovTa Kaphiav^ ovt€ tcov 
aXXcov t&S" €i77€iv ovSiv. to t€ ydp Tj7Tap TOL$ fJL€V 


1 codd. edd. varia ; corrupta et inepta seclusi. 



living for a long time. The reason for these pheno- 
mena has been explained elsewhere.] 

We have now said what is the purpose for which 
each of the viscera is present ; but also they have 
been formed of necessity at the inner ends of the blood- 
vessels, because moisture, i.e. moisture of a blood- 
like nature, must of necessity make its way out there, 
and, as it sets and solidifies, form the substance of 
the viscera. That, too, is why they are blood-like in 
character, and why the substance of all of them is 
similar, though different from that of the other 

XI. All the viscera are enclosed in membranes. Membranes. 
Some covering is needed to ensure their safety, and 

it must be a light one. These conditions are fulfilled 
by a membrane, which is close-textured, thus making 
a good protection ; does not consist of flesh, and 
therefore does not draw in moisture or retain it ; is 
thin, therefore light, and causes no burden. The 
biggest and strongest membranes are those round 
the heart and the brain, which is natural enough, as 
it is always the controlling power which has to be 
protected ; therefore the heart and the brain, which 
have the supreme controlling power over the life of 
the body, need the most protection. 

XII. Some animals possess a full complement of Variations 
viscera, some do not. We have already stated what ™sver*. 
animals have less than the full number, and the 
reason. But also, the same viscera are different in 

the various animals that have them. For instance, 
the heart is not identical in all the animals which have 
a heart ; nor is any other of the viscera. The liver 
illustrates this : in some it is split into several parts, 
in some almost undivided. This variation of form is 



avrcov rcov evalpcov Kal ^cootokcov en he fiaWov 


20 lyQvcov koll (rcov} 1 rerpaTrohcov /cat cootokcov. to he 

TCOV OpViOwV fldXiGTa 7TpO<J€fA<f>€p€$ TO) TCOV ^coo- 
tokcov eorlv Tynan* KaOapov yap Kal k'voufjiov to 
Xpcopia avrcov cart KaOdirep KaKeLvcov . alriov he. 
to rd Gcof-iara tovtojv evirvovorara etvat /cat fir) 
7ToXXr)v e%eiv cf>avXrjv TrepiTTCoaiv . htoirep evia /cat 

25 ovk e^et xoXrjv rcov ^cootokcov to yap rjnap ovp- 
fidXAerat uoXv pepos TTpos evKpaoiav rod ocopLaros 
Kal vyieiav iv pev ydp rco alfian fidXiara to 
tovtojv reXos, to 8' rjirap aipLariKcorarov pcerd rfjv 
Kaphlav rcov airXdyxvcov . rd he rcov rerpairohcov /cat 
cootokcov /cat rcov lyOvcov evcoy^pa rcov TtXeiortov, 

30 evicov he /cat tpavXa rravreXcos , coairep Kal rd oco- 
ptara (fyavXrjs rervx^Ke Kpdoetos, oiov <j)pvvr)$ Kal 
XeXcbvrjs /cat rcov dXXcov rcov rotovrcov, 

HnXrjva 8' eyei rd f.iev Keparocpopa /cat St^aAa 
urpoyyvXoVy KaOdirep atf /cat irpoparov Kal rcov 
aAAajy eKaarov, el pLTj ri hid pieyeOos evav^iarepov 
674 a h'xei Kara pr\Kos, olov 6 rod fioos TrerrovOev rd he 
rroXvox^hrj irdvra paKpov, oiov v$ Kal avOpooiros Kal 
kvcov, rd he pecovvx^ pera^v tovtojv Kal puKrov rfj 
ptev yap irXarvv e^et rfj he. orevov s oiov lirnos /cat 
opevs Kal ovos. 
6 XIII. Ov piovov he hiacfjepei rd airXdyxva rrjs 
aapKog too SyKco rod acoparos , dXXd Kal rco rrfv 2 
piev e£co rd 8' eaco rrjv Oeoiv e^^v. alnov 8' on 

1 <twv> Peck. 2 tt]v ESUYZ: id vulg. 

° See above, on 650 b 24. Cf. 677 a 19 ff. 



found first of all even among the viviparous blooded 
animals ; but it is more noticeable among the fishes 
and oviparous quadrupeds, whose livers differ not 
only from those of the Vivipara, but also from each 
other's. In birds, the liver very closely resembles 
that of the Vivipara : in both, its colour is pure and 
blood-like. The reason for which is, that their bodies 
give a very free passage to the breath, which means 
that they retain very little foul residue ; hence, indeed, 
some of the Vivipara have no gall-bladder, and this is 
largely due to the very considerable assistance given 
by the liver in maintaining a good blend a and healthi- 
ness in the body. This is because the purpose which 
these viscera serve lies chiefly in the blood, and after 
the heart the liver contains more blood than any 
other of the viscera. In most of the oviparous 
quadrupeds and the fishes the liver is yellowish, and 
in some of them it is altogether bad-looking, on a 
par with the bad blend of the rest of their bodies. 
This happens in the toad, the tortoise, and the like. 

As for the spleen : In horned animals that have 
cloven hoofs it is rounded : e.g. in the goat, the sheep, 
and similar animals ; unless greatness of size has 
made it grow out at some point lengthways, as in the 
case of the ox. In all the polydactylous animah the 
spleen is long, as in the pig, in man, and in the dog. 
In animals with solid hoofs the spleen is intermediate 
between the two and has the characteristics of both : 
in one place it is broad, in another narrow, as exempli- 
fied in the horse, the mule, and the ass. 

XIII. Now the viscera differ from the flesh not only 
in the bulkiness of their mass, but also in their 
situation, for the flesh is on the outside of the body, 
while they are inside. The reason for this is that 



rrjv </>v<jlv e^et Koivwvovaav tou? (f>Xeipi, Kal to, fjuev 
twv <f>Xefiwv ydpiv, ra 8' ovk dvev <f)Xefiwv iorw. 

10 ^COOLS, TOIS" jLt^ €)(OVGLV OLOO<f)dyOV fj TeXevTa TOVTO 

GTOfiari' rrjs oe KoiAias e^oyievov to KaXovfievov 

At' rjv S' air lav e^ei ravra ra fiopta twv t>wwv 
€KaoTOV t cfxivepov iraotv. Kal yap oe^aodai tt)v 
elueXOovoav Tpo<j>r}v Kal ttjv e^LKfiaafievrjv avay- 

15 Katov iKTT€{Ju(jai y Kal firj rov avrov tottov etvai rfjs 
T aiTETTTOV Kal TOV TreptTTWfiaTos > etval re Ttva 
Set tottov iv w pieTafidXXei. to fxev ydp ttjv ela- 
eXOovaav e^et fioptov, to oe to 7teplTTW\xa to axP 7 ?" 
utov woirep oe ^poVos* eTepos eKarepov tovtwv, 
dvay Katov 8ieiXrj<f)9ai Kal tois tottols. dXXd Trepl 

20 jiev tovtwv ev tols Trepl ttjv yeveatv Kal rrjv rpo(j>r)v 
oiKeiorepos euriv 6 StoptGfios' Trepl Be Trjs $iacf>opas 
t/J? KoiXlas Kal twv ovvTeXwv fioplwv vvv im- 
OKeTTTeov . 

OvTe ydp tols [xeyedeatv ovTe rots etBeatv ojiotas 
k'xovaiv dAA^Aots" to. £<£>a* dAA' ooa fiev eoTtv avTwv 
d}i(f)d)BovTa twv evaifjuov Kal twv ^wotokwv, filav 
25 eyjzt KoiXiav, olov avBpwiros Kal kvwv Kal Xewv Kal 
TaAAa oca iroXvhaKTvXa, Kal ooa [iwvvya ) olov 
liriros, opevs, ovos, Kal ooa St^aAa i±ev dfi^whovTa 
84, olov vs, ttXtjv el 1 ti hid fieyeOog tov awjiaTOS 

1 vo-nX^ fj el ESUY (rj om. E) : vottX^ ttX^v el P et corr. 
U : vanX-qy^ in ras. et supra kol x°ip°$ Z 2 , turn -nXrjv el Z 1 : vs, 
el pr\ Bekker : vs, ttXtjv el \rr\ Buss. 

° See Be gen. an. Bk. II. chh. 6 and 7. 



their nature shares that of the blood-vessels : some 
of them exist for the sake of the blood-vessels, 
others do not exist apart from the blood-vessels. 

XIV. Below the diaphragm is the Stomach, which stomach 
is placed where the oesophagus ends (if there is an i^ estine 
oesophagus ; if not, immediately next to the mouth). 
Next after the stomach and continuous with it is what 
is called the Gut. 

It must be obvious to everyone why all animals 
have these parts. It is a necessity for them to have 
some receptacle for the food they take in, and to 
expel it again when its moisture has been extracted 
from it ; and there must be two different places for 
these two things— the unconcocted food and the 
residue ; there must also be another place in which 
the change from one to the other is effected. Two 
receptacles, then, one for the incoming food, one for 
the residue which is no more use — as there is a 
separate time for these so there must be a separate 
place. However, it will be more appropriate to go 
into these matters in our treatise on Generation and 
Nutrition* At the present we must consider the 
variations that are to be found in the stomach and its 
subsidiary parts. 

The stomach differs both in size and appearance in 
different animals. Those of the blooded Vivipara 
which have front teeth in both jaws have one 
stomach ; e.g. man, the dog, the lion, and the other 
polydactyls ; so also those that have solid hoofs, 
e.g. the horse, the mule, the ass ; and those which 
although they are cloven-hoofed have front teeth 
in both jaws, e.g. the pig. These rules apply unless 
the size of the frame and the character of the food 



674 a ^ 

/cat t?]V rrjs rpocfirjs hvvajiLVj ovoav ovk evnenrov 

30 dAA' aKavdcohrj Kal ^vXiKrjv, e^ei TrAciof?, oto^ 

/cajLt^Ao?, cooirep Kal ra KepaTO<f>6pa- ra yap 

Keparocf)6pa ovk eariv dfitpcbhovra. hid tovto he /<:at 

?7 KaiirjXos oi) tcov dficf)Coh6vTCov eorlv, aKeparog 

ovcra, hid to dvayKaiorepov etvai avrfj tt)v KoiXLav 

e\eiV TOiaVTTjV Tj TOl)$ TTpOCtQloVS 6hoVTaS . COOT 
674 b 677€t TaVT7)V OflOLaV €)(€L ToXg {JLTJ d{l(f)CohoVGLj Kal TCL 

irepl rovg dSoVra? ofioicos e%ei avrfj, cos ovhev ovras 
Trpoepyov. d{ia he Kal eirel r) rpocprj aKavOcohrjs, 
ttjv he yXcorrav dvayKT] uapKcbht) etvai, irpos 
aKXrjpoTrjra rov ovpavov KaraKexprjTai tco Ik tcov 

5 ohovTcov yecohei rj tfivois. Kal firjpvKa^ei S* r) 
Kafi7]Xos coarrep rd KepaTOcf>6pa , Sid to rag KoiXias 
dfiolas e^eiv tols K€paro<f)6poLg. tovtcov V eKaarov 
TrXeiovs e%ei KoiXias, olov irpofiarov, ftovs, al'£, 
eXachos, Kal rdXXa ra rotavra tcov ^cocov, oncog 
eTreihr) Trjs epyaolag eXXelrrei irepl ttjv Tpocf>rjv r) 

io Xeirovpyia r) tov GTopLaros hid ttjv evheiav tcov 
ohovTcov, r) tcov koiXlcov €Tepa Trpos eTepag Se^Tai 1 
rrjv Tpotf>r)v, r) fxev aKarepyaorov , rj he. Kareipya- 
Gfiivrjv fiaXAov, r) he TrdpLTrav, r) he Xelav. hid ra 
TOiavra tcov ^cocov TrXeiovs e%ei tottovs Kal jiopia. 

15 KaXovvrai he Tavra KoiXla Kal KeKpvcpaXog Kal 
i)(ivos Kal rjvvGrpov. ov S' e^€t Tpoirov ravra irpds 

1 Se^rat Peck : Bexofxevrj vulg. 



modify them : for instance, if the food is thorny and 
woody and therefore not easy to concoct, in which 
case the animal has several stomachs, e.g. the camel ; 
so also have the horned animals, as they have not front 
teeth in both jaws. Thus also the camel has not the 
two rows of front teeth either, although it has no 
horns ; this is because it is more necessary for the 
camel to have several stomachs than to have all these 
front teeth. So, as it resembles the animals which 
lack the upper front teeth in that it has several 
stomachs, therefore the arrangement of its teeth 
is that which normally accompanies the multiple 
stomachs : in other words, it lacks these front teeth, 
as they would be no use to it. And also, as its food 
is thorny, and as the tongue has of necessity to be 
of a fleshy character, Nature has made use of the 
earthy matter saved from the missing teeth to make 
the roof of the mouth hard. Again, the camel 
ruminates as the horned animals do, because it has 
stomachs that resemble theirs. Every one of the 
horned animals (such as the sheep, the ox, the goat, 
the deer, and the like) has several stomachs ; and the 
purpose of them is this : Since the mouth is deficient 
in teeth, the service which it performs upon the food 
is deficient ; and so one stomach after another 
receives the food, which is quite untreated when it 
enters the first stomach, more treated in the next, 
completely treated in the next, and a smooth pulp 
in the next. And that is why these animals have 
several such places or parts, the names of which are 
(1) the paunch (rumen), (2) the net or honeycomb-bag 
(reticulum), (3) the manyplies (omasum), (4) the reed a 
(abomasum). For the relation of these to each other 

Or, true stomach. 

K2 291 


674 b 

aAA?yAa rfj Oeaet /cat tols eiheaiv, e/c re rrjs laropias 
rrjs 7T€pl ra twa Set dewpelv /cat 4k twv dvaTopLwv. 

Atd T7]v avrrjV S' alrlav /cat to twv dpviOwv 
yivos Bta<f)opav Trepl to Trjs Tpocfrrjs Se/crt/coV 

20 jiopiov. iirel yap ovoe ratrra dXws ttjv tov gto- 
IMLtos airohihwui XeLrovpylav (aVoSoyra yap) /cat 
ovO* w StatprjoeL ov9* w Xeavel ttjv Tpo(f>rjv ej(ovaiy 


KaXovfievov irpoXofiov 6\vti ttjs tov GTOfiaTos ipya- 
aLas, oi ok tov OLGO<f>dyov irXaTVV, rj rrpo tt\s KOiXLas 
25 avTov jiipos tl oyKwoes iv w TrpoO-qaavpL^ovat ttjv 
aKaripyauTOV Tpo<j>r)v s rj Trjg kolXlcls avTrjs tl 
eTraveoTTiKos, oi S' avTrjv ttjv kolXlolv laxvpav kol 
aapKcohrj Trpos to hvvaoQai ttoXvv %povov OrjaavpL- 


Swdfiet yap /cat Tjj OepfioTTjTi tt\s KoiXlas rj <f>voLS 
80 dvaXafipdv€L ttjv tov GTOjxaTos evoeLav. elal 8i 
TLves ol tovtwv ovhev exovaLV, dXXd tov TrpoXofiov 1 
fiaKpov, oaa fiaKpoGKeXij /cat I'Aeta, Std ttjv ttjs 

TpO(f)T)S VypOTTJTa. aLTLOV 8' OTt 7} Tp0<f>7] 7T&GL 

tovtols evXlavTOSy wgt€ avfi^au'eLV Sta raura twv 
tolovtwv Tas /cotAta? elvaL vypds [Std ttjv direiplav 
Kal ttjv Tpo(f>rjv]* 
675 a To oe twv l^Ovcov yivos e^et fjiev oSdvras, tov- 


oXiyov ydp tl 4gtl yivos to put] tolovtov, olov 6 
KaXovpLevos OKapos, os S?) /cat So/cet firjpvKd^eLv 

1 7Tp6Aofiov] orofiaxov Ogle, collato Hist. An. 509 a 9. 
2 seel ud en da. 
3 names Ogle : TTavra$ vulg. 

a At 507 a 36 ff. b The gizzard. 

e Ogle reads " oesophagus. 1 ' 



as regards position and appearance, the Researches 
upon Animals a and the treatises on Anatomy should be 

The same reason as has just been described accounts 
for the difference which presents itself in birds in the 
part which receives the food. Birds, like the other 
animals, do not get the full service from the mouth in 
dealing with the food — since they have no teeth at 
all, and they have nothing with which to bite up or 
grind down the food ; and so some of them have, 
before the stomach, what is called the crop, to per- 
form the work instead of the mouth. Others have 
a broad oesophagus ; or their oesophagus has a 
bulge in it, just before it reaches the stomach, in 
which they keep a preliminary store of untreated 
food ; or some part of the stomach itself sticks out. 
Others have a strong and fleshy stomach b which 
is thus able to store the food up for a long period 
and to concoct it although it has not been ground 
down ; thus Nature makes up for the deficiency of 
the mouth by means not only of the heat of the 
stomach but also by its special character. Other 
birds have none of these devices, but a long crop, c 
because their food is moist : these are the long-legged 
marsh birds. The reason for this is that the food 
which all of these take is easily ground down, and 
the result is that the stomachs of birds of this sort 
are moist [owing to the unconcocted and moist state 
of the food]. 

The tribe of fishes have teeth : practically all have 
saw-teeth. There is one small group to which this 
does not apply, e.g. the Scams,* 2 as it is called, and 
it seems reasonable to suppose that this is why 

d The parrot-fish ; see above, 662 a 7. 



5 evXoytos Std ravra (xovos' Kal yap rd fir) dficf>cb- 
Sovra Keparocf)6pa Se firjpvKd^ei. diets' Se 7rdvras x 
e^ovcrtv, coore BceXelv fiev ovvavrai, tfravXcos 8e 81- 
eXetv ivSiarpifieLV yap ovx otov re -^povi^ovra?' Std- 
irep ovSe irXarelg eyovaiv oSovras, ot3S' eVSe^e- 
rai Xeaiveiv fidrrjv av ovv €?^oi'. k'ri Se orofiaxov 

10 ol fiev oXcos ovk exovoLV, ol Se fipaxvv. dXXd irpos 
rrjv fiorjOeiav rrjg Treifjecos ol fiev dpviQcoheis kxovoi 
rds KoiXias Kal oapKcoSetg, otov Keorpevs, oi 8e 
7toXXol irapa rrjv KoiXlav dirocfyvdhas ttvkvols, lv 
iv ravrais cocnrep iv rrpoXaKKLOtg Brjaavpc^ovres 

OVOOTjTTCDOl Kal 7T€TT(DOl TTjV rpO(f)r}V. e^OUCTt 8' 

is ivavritos oi lx@v€$ rois dpvioi rd? a7TO<f)vd$as' ol 
fjiev ydp ix^ves dvco irpds rfj koiXlcl, rcov 8* opviOcov 
ol exovres a7rocf>vdoas Karco irpos rco reXei rod 
ivrepov. e^oucrt 8' d7TochvdSas evia Kal rcov £>too- 
toklov ivrepiKas Karco 8id rrjv avrrjv alrlav. 
To Se rcov IxOvcov yivos djrav, Std to ivSeecrepcos 

20 ex^iv rd TTepl rrjv rrjs rpocf>rjs ipyaalav, dXX 
arrerrra Siaxcopeiv, Xaifxapyov rrpds rrjv rpocfuqv 
Ian, Kal rcov dXXcov Sk rrdvrcov ooa evQvivrepa- 
rax^tas yap yivojiivr]s rrjs Siaxtoprjoecos, Kal 8td 
ravra f^pax^ias ovorjs rrjs drroXavoecos, rax^cav 
dvayKalov yiveodai 7rdXiv Kal rrjv iiriBvpLiav, 

25 Td 8' dficpcoSovra on fikv puKpav c^ei KoiXiav 
elpryrai rrporepov els Siacf)opds Sk rrlrrrovoi hvo 
Traoat cr^eSoV ra jikv yap rfj rrjs kvvos ofiocav 

1 Travras S : iravTts vulg. 

° Probably some kind of mullet. 
b " Caecal appendages " (Ogle), or " alimentary sacs.** 
c The vermiform appendix. 



it alone ruminates, for horned animals which have no 
teeth in the upper jaw also ruminate. All teeth in fish 
are sharp ; this enables them to bite up their food, 
though somewhat unsatisfactorily ; this is because 
they cannot spend long over mastication ; hence 
they neither have flat teeth nor may they grind 
the food down ; therefore it would be idle to have 
the teeth. Furthermore, some fishes have no gullet 
at all, others have a short one ; but, in order to as- 
sist the process of concoction, some of them, like the 
Kestreus, a have fleshy stomachs, similar to those of 
birds ; the majority, however, have a large number 
of appendages b by the side of the stomach, in which 
to store up the food as it might be in additional cellars 
and there putrefy it up and concoct it. The ap- 
pendages of fishes are, however, quite different from 
those of birds. In fishes they are fairly high up 
beside the stomach, whereas when present in birds 
they are down below at the end of the gut. Some 
of the Vivipara also have appendages c of this latter 
kind, and their purpose is the same. 

The whole race of fishes is gluttonous for food, 
because their equipment for reducing it is defective, 
as a result of which most of it passes through un- 
concocted. Of all, those which have a straight intes- 
tine are especially gluttonous, since the food passes 
through quickly, which means that their enjoyment 
of it is brief, and therefore in its turn the desire for 
food must come on again very quickly. 

I have already said that in animals with front 
teeth in both jaws the stomach is small. These 
stomachs fall into two main classes. Some have a 
stomach resembling that of the dog, some that of 



e^ovoi KoiXlav, ra Se rfj rijs uos" eart §' rj jxev rrjs 
vos fiel^wv /cat rivas k'xpvoa fierpias rrXaKas 7rpds 
to xpoviwrdpav ylveudat rrjv rreipLv, rj Se rrjs kvvos 
30 jut/cpa to [xeyeOos /cat ov rroXv tov ivripov vrrep- 
fidXXovoa /cat Aeta ra. cvtos* fxera yap rrjv /cotAtav 
rj twv ivrepojv ey/cetTat (fyvoLS irdaL rots ^cools. e^et 
he Sta^opa? iroXXds, KaBdrrep rj /cotAta, /cat tovto 
to [Aopiov. tols fxev yap drrXovv eart /cat Sfioiov 
dvaXvofievov, tols S' dvofioiov evloLs fxev yap evpv- 

35 TepOV TO TTpOS Tjj /COtAta, TO &€ 7TpOS TCO TeAet 

arevorepov 1 (SioTrep at Kvves fiera ttovov rrpotevTac 

675 b TTjV TOiaVTT)V TT€pLTTWGLv) , TOLS he TrXeloOLV dvwOeV 

GTevorepov, 1 irpos tco riXeL 8' evpvrepov. 

Met£a> he /cat dvaSt77Acoa€tj e^ovra TroAAas" t<i 


tovtols fxei^ovs Kal twv evrepwv Sta to fieyeOos' 
5 rravra yap ws elTreiv pceydXa ra Keparo<j>6pa Sta 
t^v Karepyaalav rrjv rrjs Tpo(f>fjs. iraoi he tols p*?) 
evdvevrepoLs rrpoXov 2, evpvrepov ylveraL to fiopLov 
tovto, Kal to KaXovfievov koXov g^ovcl, /cat tov 
Ivripov TV(f>X6v tl Kal oyKcohes, elr €K tovtov 
7raAtv orevorepov* Kal elXiypievov, to he fierd 
io toOto ei9i> rrpos ttjv e^ohov StaTetVet tou uepLT- 
TWfiaTos, Kal tols fiev tovto to puopLov, 6 koXov- 
fxevos dpxos, KVLodihrjs earl, tols V drrLpieXos* 
iravra he ravra jLtejLt^^av^Tat rfj cf>vaeL rrpos tols 
dpfioTTOvaas epyaalas rrepl rrjv Tpo<f>rjv Kal tov 
yLvofiivov 7TepLTTi6fiaT0$. TTpo'iovTL yap Kal Kara- 
fiatvovTL to) 7reptTTO)ftaTt evpvxajpia yiverat, /cat 
15 rrpos to p,eraf$dX\eLv Larafievu) tols evx^Xorepots 
1 OTcvwrepov bis vulg. 2 npoTov Peck : irpotovaiv vulg. 

3 OT€VOTepOV SU : OT€VU)T€pOV VUlg. 



the pig. The pig's stomach is larger than the dog's, 
and it has some folds of medium size, so as to prolong 
the time of concoction. The dog's is small in size — 
not much bigger indeed than the gut, and its inner 
surface is smooth. The gut has its place next after 
the stomach in all animals. Like the stomach, this 
part too presents many various forms. In some 
animals it is simple and similar throughout its 
length, when uncoiled ; in others it is not similar 
throughout. Thus, in some it is wider near the 
stomach, and narrower towards the end (that is why 
dogs find difficulty in discharging their excrement) ; 
in the majority, however, it is narrower at the top, 
and wider at the end. 

In the horned animals, the intestines are longer and 
have many convolutions ; and their bulk (as well as 
the bulk of the stomach) is greater, owing to the size 
of the animal : horned animals being, on the whole, 
large in size because of the ample treatment which 
their food receives. Except in those animals where 
it is straight the intestine gets wider as it proceeds, 
and they have what is called the colon and the 
blind and swollen part of the gut a ; and then after 
that point it gets narrower again and convoluted. 
After this, it goes on in a straight line to the place 
where the residue is discharged ; and in some this 
part (which is called the anus) is supplied with fat, in 
others it is devoid of fat. All these parts have been 
devised by Nature to suit their appropriate functions 
in treating 1 the food and in dealing with the residue 
produced. As the residue proceeds on its way and goes 
downwards, it finds a wider space where it remains 
in order to undergo transformation ; this is what 

a The caecal dilatation. 



> b 

rwv ^ohdv Kal TrXeiovos Seofievois rpo<f>fjs, Sid rd 
fieyedos r) rr)v Oepfiorrjra rcov rorrwv. elr* eV- 
revdev 77aAiT>, tboirep oltto rrjs dva> KoiXlas Se^cTat 
arevorepov 1 evrepov, ovrtos £k rod kojXov Kal rrjs 
evpvxojpias iv rfj Kara) kolXlo. rrdXiv els arevo- 

20 repov 1 k'pxerai Kal els rrjv eXiKa ro 7Teplrra>fJLa 
i^iKjiaujievov 7rd[JL7Tav s ottojs ra\iievr\rai r) <j>vois 
Kal fir) ddpoos fj rj e^oSos rod TrepirruypLaros* 

°Oaa fiev ovv elvai Set rayv ^tocov aa>(f)povearepa 
7rpos rrjv rrjs rpo<j>rjs Trolrjoiv evpvxtoptas fiev ovk 
€^€t fieydXas Kara, rr)v Kara) KoiXiav ) eXiKas S' 

25 e'xei rrXelovs Kal ovk evOvevrepd eanv. r) piev ydp 
eupt^topta TTOiei rrXrjdovs emOvpiiav , r) S* evOvrrjs 
rayyrrjra imQv\Lias* oiorrep ooa rcov t^tocov rj drrX&s 

€^€6 Tf €l)pVX<£pOVS TOLS VTToSoxdSj TCL fieV eiS TrXrjBoS 

yaarptjiapya rd §' els rdxos iariv. 

'JLrrel S' iv rfj dvo) fiev kolXlq Kara rr)v Trpwrrjv 

so etcrohov rrjs rpo<f>rjs veapdv dvayKatov elvai rrjv 
Tpo^rjVy Kara) he rrpo'Covaav KOTrpcoSrj Kal i£- 
iKfiaGfievrjv, dvayKatov elval ri Kal to fiera^v, 
ev to fierapaXXet Kal out' en Trpoacparos out* rjhrj 
Koirpos. §ta rovro uavra rd roiavra £a)a rrjv 
KaXovfievrjv e'xei vrjoriv Kal ev rw fierd rrjv KoiXiav 

85 ivrepw rtp Xerrrco- rovro yap jiera^v rrjs t dvw 3 ev 
fj ro anerrrov t Kal rrjs Kara) } ev fj ro dxp^orov rjhrj 
Treplrrajfia, ylverai S' iv iraoi jxev, SrjXrj §' iv rots 

1 oT€\d)T€pov bis Langkavel. 

° i.e. the " stomach." 
b i.e. the " large intestine." 



happens in the animals which need and take more 
food owing either to their size or to the heat of these 
parts of the body. After this, just as it goes into a 
narrower part of the intestine after it leaves the upper 
gut, a so also it goes into a narrower channel after 
the colon or wide part of the lower gut, & and into 
the spiral coil ; into these the residue passes when 
its juices have been completely exhausted. In this 
way Nature is enabled to keep the material in store, 
and the residue is prevented from passing out all at 
the same moment. 

In those animals, however, which have to be more 
controlled in their feeding, there are no great wide 
spaces in the lower gut, but their intestine is not 
straight, as it contains many convolutions. Spacious- 
ness in the gut causes a desire for bulk of food, and 
straightness in the intestine makes the desire come 
on again quickly. Hence, animals of this sort are 
gluttonous : those with simple receptacles eat at very 
short intervals of time, those with spacious ones eat 
very large quantities. 

Since the food in the upper gut, when it has just Jejunum, 
entered, must of necessity be fresh, and when it 
has proceeded further downwards must have lost its 
juices and be practically dung, the organ which lies 
between the two must of necessity be something 
definite, in which the change is effected, where food 
is no longer fresh and not yet dung. Therefore all 
animals of this sort have what is called the jejunum, 
which forms part of the small intestine, which is next 
to the stomach. That is to say, it has its place 
between the upper gut, where the unconcocted 
food is, and the lower gut, where the now useless 
residue is. All these animals have the jejunum, but 



676 a fiet^OOl KCLL V7](JT€VOaOLV aAA' OVK iBrjBoKOGLV TOT€ 

yap Brj 1 otov 2 fieratx^ov ylverai rcov rojrcov dp<f>o- 
repcov, iBrjBoKorcov Be pLLKpos 6 Kaipos rrjs fiera- 
j8oA?Js. roXs fJiev ovv 9f]Xeai z yiver ai orrov dv rvxjj 

5 rod dvco ivrepov rj vrjons' ol §' dppeves* e^ovGL rrpo 
rod rv<f)\od Kai rfjs Karen /cotAtas". 

XV. "E^oucrt Be rrjv KaXovfievrjv rrverlav rd fiev 
TToXvKoiXia Ttdvra, rcov Be [xovokolXIcov Bacrvirovs* 
eyet Be rd eyovra rcov ttoXvkolXlcov rr)V uveriav ovr 
ev rr\ pceyaArj kolAio. ovr ev rev KeKpvcpaAco ovr ev 

io rep reXevraico rep rjvvarpcp, dXX iv rep p^era^v rov 
reXevralov Kal [Suo] 5 rcov npcorcov, iv rco KaXov- 
fievco e^tVoi. exei Be ravra rrdvra rtverLav Bid rr\v 
Traxvrrjra rov ydXaKros' ra Be fiovoKoiXia ovk 
e^et, Xe7rr6v yap ro ydXa rcov pbovoKOiXlcov. Bid 
ra>v fiev Keparo<j>6pcov nryyvvraiy ra>v S' aKeparcov 

is ox) rr-qyvvr ai ro ydXa. rep Be BaavvroBi yiver at 
rrverla Bid ro vepLeaOai ottcoBt] iroav 6 yap roiov- 
ros x v f x ^ (JWLorrjow iv rfj KoiXia ro ydXa rots 
ifxfipvoLS. Biori Be rcov ttoXvkoiXIcov iv rep ix iVC P 
ylverai r) rrverla, eiprjrai iv rols 7TpopXr)pLaoLV. 

1 S77 Z : 77S77 vulg. 
2 olov PZ, om. vulg. 
3 d-qXeai] reAeiot? Z : TrXeLoai Piatt. 

4 dppeves] KVV€S Piatt. 

5 [hvo] secludendum. 

This seems to mean that when the animal is fasting the 
two receptacles do not bulge, and so the jejunum is visible; 
and though after the animal has fed you might expect to see 
the jejunum^ because it should be full of food which is being 



it is apparent only in the larger ones, and in them 
only when they are fasting, not when they have 
recently been eating, for when they are fasting, there 
is an interspace between the two receptacles, whereas 
when they have been eating, the time taken by the 
change is short.® In females the jejunum can have its 
place in any part of the upper intestine ; in males 
it is placed immediately before the caecum and the 
lower gut. 

XV. What goes by the name of Rennet is present Rennet 
in all animals which have a multiple stomach ; the 
hare is the only animal with a single stomach which 
has it. In the former class the rennet is not in the 
paunch b nor in the reticulum, nor in the abomasum (the 
last of the stomachs) ; but in the stomach between 
the last one and the first ones, i.e. the so-called 
omasum (manyplies). All these animals have rennet 
because their milk is so thick ; similarly, the single- 
bellied animals have no rennet, because their milk 
is thin. This also explains why the milk of horned 
animals coagulates, while that of the hornless does 
not. As for the hare, it has rennet because it feeds 
on herbs with fig-like juice ; and this juice can 
coagulate the milk in the stomach of sucklings. I 
have stated in the Problems* 1 why, in the animals 
that have many stomachs, the rennet is formed in 
the manyplies. 

transmuted inside it (see above, 675 b 32), it is not visible, 
because the change is effected so rapidly. 

b Lit. " the great stomach.'* 

c See above, 674 b 14 ff. 

d No such reference can be found. 


Tov avrov ok Tponov to, 7repl to, GTrXdy)(ya 


tols rerpaiTOGi fiev cootokols 8e twv ^cocov Kal tols 
25 airoGiVy olov rois ocj>€GLV. Kal yap rj TCOV ocfxEcov 
<f>VGis earl ovyyevrjs tovtols' ofioLa yap eon aavpcp 


irdvTa TraparrXriGia, ttXtjv tcz fiev eyei nXevfiova oca 
to ire^eveiv, oi 8* ovk €)(ovglv, aXka fipdyxia dvTi 
tov TrXevfjLovos. kvgtiv 8' ovd* oi l^Oves eypvoiv 
30 ovtc tovtojv ovhev 7tXt)v ^eXwvqs' TpeTrerai yap eis 
Tag (jioXloas to vypov oXiyoTroTOJV ovtwv hid ttjv 
avai\i*0TJ}Ta tov TrXevyiovos , KaOdrrep toIs opvLGiv 
els tol TTTepd. kol ejnXevKaivei he to TrepLTTOjfia 

tols exovcrt KVGTIV itjeXOoVTOS TOV 7T€piTT0>lXaT0S 

v<f>LGTaTaL aXfAvpls yecoSrjs iv tols dyyelois' to ydp 
yXvKi) Kal TTOTipiov dvaXtGKeTaL old KovcfyoTfjTa els 
Tas odpKas. 

676 b TaJV 8' S(f)€a)V Oi €^€t? TTpOS TOVS dXXoVS k'^OVGl 

T7]v avTrjv oia(f>opdv rjv Kal iv tois L)(dvGL tol 
GeXdxv} TTpos tovs dXXovs' ^wotokovgl yap k'^co Kal 
Ta GeXd^f] Kal oi e^ets 1 , iv avTols tpoTOK-qoavTa 
TTpCOTOV. pLOVOKOl'Xia he irdvTa to. ToiavTa ioTi, 

1 fxciKpw Y : fiaKpto rj vulg. 2 hiort Ogle : Bioirep vulg, 



What has been said already on the subject of the 
viseera, the stomaeh, and eaeh of the other parts 
mentioned, applies to the footless ereatures (such as 
the Serpents) as well as to the oviparous quadrupeds. 
Indeed, the Serpents are akin to these : for a serpent 
is like a long and footless lizard. A third elass in 
whieh all these parts are similar is the Fishes : the 
only difference is that the first two elasses are land- 
ereatures and therefore have a lung, whereas fishes 
have no lung but gills instead. Fishes have no 
bladder, nor has any of these ereatures (exeept the 
tortoise) ; the reason is that they drink little (beeause 
their lung is bloodless), and the moisture in them 
is diverted to the horny seales, just as in birds it is 
diverted to the feathers. And in all these ereatures, 
as in birds, the residue a is white on the surface, 
since in those animals that have a bladder, when the 
residue has been voided an earthy salt deposit 
settles in the vessels, the sweet and non-briny por- 
tion, owing to its lightness, being used up upon the 

The Vipers have the same peculiarity among the 
Serpents as the Selaehia have among the Fishes. 
Both of them are externally viviparous, though 
they first produee their ova internally. All these 

a See Introduction, pp. 32 ff. 



i b 

5 KaBairep rdAAa rd dfufxjoSovra' Kal oirXdyxya Se 
rrdjiTrav jiiKpd e'^et, oooirep raXXa rd fir) exovra 

KVCJTLV. Ot S' 0<f)€L£ St(X T7]V TOV GOOjJLaTOS fJLOp<f>T}V, 

onXdyxycov e^ouat Sta ravra [laKpd Kal rots rcov 
dXXwv ^cocov dvopLota, Sta to Kaddrrep ev tvttco rd 

10 oxrjfjLar* avrcov TrXaaOrjvai Sta tov rorrov. 

'EttlttXoov Se /cat fieaevrepLov Kal rd irepl rrjv 
rcov evrepcov (jyvaiv, en Se rd Sia£a>ju,a Kal rrjv 
/capStav Trdvr e'^ei rd evat^ta rcov c^cpoov, TrXevfiova 
Se Kal dprrjplav irdvra 7rXrjv rcov l^9va)v. /cat rrjv 
deoiv Se rrjg dprrjplag Kal rod olaocpdyov rravra 

15 to. k'xovra 6p,olco$ e'^et Sta rds elprjfjLevas alrias 


II. 'E^et Se /cat ^oAi^v rd 7roAAd rcov evalpioov 
t s oooov ) rd \xev eVt too rjTrari, rd 8' dTTrjprrjjjievrjv em 
tols evrepois, cog ovaav oi>x rjrrov e/c rrjg Karoo 
KoiXlag rr)v <f>vcnv avrrjg. SrjXov Se i±dXiar eirl rcov 

20 IxBvcov ouroi yap k'xoval re irdvres, Kal ol 7roAAot 
7700? Tot? 1 ivrepoLs, evtot Se Trap" 6'Aoy to evrepov 
TTapvcfyaapievrjv, olov rj a/xta* /cat rcov dtfieoov ot 
7rAetorot rov avrov rpoirov. Storrep ol Xeyovre? rr)v 
(f>vcriv rrjg ^oA^s" aloBiqoedos rivos elvai X a P lv °^ 
KaXcbg Xeyovoiv* tf>aol yap elvai hid rovro, oircog 

25 rrjs ipvxfjs rd irepl rd rjirap jioptov oaKvovoa fiev 
avvLurfj, Xvopievrj S* tAecov Trotfj' rd fiev yap SXoos 

1 toi? PYZ et co it. U : om. viilg. 

a See 665 a 10 ff. b See 650 a 14. 

c This seems to refer to the views expressed in PJato, 
Timaeus, 71 d. 


creatures have one stomach only, as do the other 
animals that have front teeth in both jaws. And 
their viscera are quite small, as are those of the 
other creatures which have no bladder. However, 
on account of the shape of the serpents' bodies, 
which is long and narrow, the shape of their viscera 
too is consequently long, thus differing from those 
of other animals. This is because the shape of them 
is fashioned, as though in a mould, on account of the 
space available for them. 

All blooded animals have an omentum, a mesen- 
tery, and the whole intestinal equipment ; also a dia- 
phragm and a heart ; and all but the fishes have a 
lung and a windpipe too. The relative positions of 
the windpipe and the oesophagus are the same in all 
of them. The reasons for this have been given 

II. The majority of the blooded animals have a Gall-bladder 
gall-bladder in addition. In some it is placed up an blle * 
against the liver ; in others it is separate from the 
liver and placed against the intestines, indicating 
that equally in these its derivation is from the lower 
gut. & This is clearest in the fishes, all of which have 
one, and in most of them it is placed against the 
intestines, though in some it runs along the Avhole 
length of the intestine, like a woven border, as in 
the Amia ; a similar arrangement is found in most of 
the serpents. Hence, those who assert that the gall- 
bladder is present for the sake of some act of sensation 
are wrong. They say its purpose is as follows : — 
on the one hand (a) to irritate that part of the Soul 
which is around the liver, and so to congeal it c ; and 
on the other hand (b) by running free to make that 
part cheerful. This cannot be true ; because some 



ovk ex €l X°^V V > °^ ov ^ 7T7T0 ^ Kai opevs Kal ovos Kal 
eXa(f)og Kal rrpo^* ovk e^ei 8' ouS' rj KdfJLTjXos 
a7TOK€KpLfjL€vrjv ) dXXd cfiXifiia ^oXcoSrj fjL&XXov* OVK 
€X ei 8' oi)S' rj (j)d}Krj xoXrjVj ovSe tcov daXarriaJV 
30 $eX(f)LS' iv Se rots' yiveoi rots clvtols tol fiev eyeiv 
(ftalverai tol 8' ovk tx eiv > °^ ov e ' v TC ? T ^ )V H-v&v* 
tovtcov V iorl Kal 6 dvOpcouos , ivioi \xkv yap 
<f>alvovrai exovres x°^W ^ 7T ^ T °v yjiraros, evioi S' 
ovk exovres' Sto Kal ylverai djji<f)icjfir]Trjo'is irepl 
oXov tov yivovs' ol yap ivrvxovTes oTrorepcooovv 

3o €XOVOL 7T€pl TtaVTOJV VTToXayL^dvOVGLV cos dirdvTcov 
iXOVTCOV. Cri>/x/?CuWi §€ TOLOVTOV Kal 7T€pl TO, 7Tp6~ 

fiara Kal tols alyas* ra fxiv ydp rrXelora tovtcov 
677 a e^et x°^W> aAA' iviaxov [lev Tooavrrjv coare SoKelv 
ripas elvai ttjv v7T€pPoXrjv y olov iv Nafo), iviaxov 
S' ovk exovuiv, olov iv XaA/aSi Trjs EijSotas' Kara 
nva ronov rrjs %a>pas* avrcbv. ert Se, cooirep eiprj- 
e rat , rj rcov IxOvcov a^pr^rai ttoXv tov ^Varos*. 
ovk opOcos 8' ioiKaoiv ol rrepl ^ Ava^ayopav V7TO- 
Xapifidveiv cos alrlav ovoav rcov o^icov voorjfxdrcov' 
virepfidXXovuav yap diroppaiveiv irpos re tov ttXcv- 
pLova i<al rag cfiXifias Kal tol rrXevpd. o^eSoV yap 
of? ravTa ov}xf$aiv€i tol TrdOrj tcov voocov, ovk 
io exovoi x°Xr}Vy iv re rats avarop.ais av iyiveTO tovto 
cf>av€p6v €tl 8e to irXfjOog to t iv toIs dppcooTrj- 
piauiv vndpxov Kal to aTroppaivopievov dovfjL^XrjTOV. 
dXX* eoLKev rj X ^ 1 ?' KaOdrrep Kal rj Kara to d'AAo 

a This is true of quite a number of species, and as Aristotle 
says, the gall-bladder is specially variable in mice. In man, 
its absence is rare ; and Aristotle's statement may well be 
derived from his observation of aborted embryos, in which 
the gall-bladder develops somewhat late. 



animals have no gall-bladder at all, such as the horse, 
the mule, the ass, the deer, and the roe ; and the 
camel has no distinct gall-bladder, but what would 
better be described as consisting of small biliary 
vessels. There is no gall-bladder in the seal, nor 
(among sea-animals) in the dolphin. Sometimes in 
the same group there are some animals which look as 
if they have one, and some as if they have none ° : 
This is true of the Mice ; and also of the human 
species, as in some individuals the gall-bladder is 
placed against the liver and is obvious ; while in some 
it is missing. The result of this has been a dispute 
concerning the group as a whole. Whatever an 
observer has found to be the condition of the indi- 
viduals he happens to have seen, that he holds is true 
of every individual throughout the group. The same 
has occurred with regard to sheep and goats, most of 
which have a gall-bladder ; but, whereas in some 
individuals it is so large that its excessive size is 
portentous (e.g. in Naxos), in others it is entirely 
absent (e.g. in a particular district of Chalcis, Euboea). 
A further point, already mentioned, is that in fishes 
the gall-bladder is separated from the liver by a good 
distance. Moreover, it is safe to say that Anaxa- 
goras's school is wrong in holding that the gall-bladder 
is the cause of acute diseases : they say that when it 
gets too full it spurts its liquid out into the lung and 
blood-vessels and sides. This must be wrong, because 
nearly everyone who suffers from these affections 
actually has no gall-bladder, and this would be proved 
if they were dissected. Besides, there is no com- 
parison between the amount of bile which is present 
in these ailments and that which is emitted from the 
gall-bladder. No ; it seems probable that, just as the 



ucbjia yivofiivrj TrepiTTa)\.id rt eoTiv r) avvrrj^is, 
ovtco Kal rj errl tw rjiTOLTt X ^ 7 ) 7T€pLTrojfia etvai KCLl 

15 OVX €V€KOL TLVOS, COGTTep Kdl 7] Iv TTJ KOiXlq, Kal 

ev tols evrepois VTrooracris. KaraxprjraL fiev ovv 
evioTe rj cf>voLs els to d)(f>eXL(jLov Kal tols rrepLTTCo- 
yLaviv, ov jjltjv Slol tovto Set t^Telv ndvTa eveKa 
tlvos* dXXd tlvwv ovtqjv tolovtlov €T€pa i£ avayKrjs 
crvpLpalveL olcl ravra rroXXd. 
"Qools fiev ovv r) rod rjirarog avaraaig vyieivr] 

20 Ioti kcll r) rod atfiaros <f>vuLS yXvKela r) els tout* 
aTTOKpivopLevrj, ravra fiev r] TrdfiTrav ovk layei* X°^ r ) v 
errl rod rjTTOLTOs, r) ev tlgl <f)XefHois , rj ra fiev ra S' 
ov. Sto Kal ra rjrTara ra tcuv dxoXwv evxP 00 Kal 
yXvKepd euriv d>s enl-nav elnelv, Kal twv exovTajv 

25 X°^h v T ° vtto T V X°^fi T °v TjiraTos yXvKvrarov 
eoriv. tqjv Se GWLGTa\ievojv e£ tjttov KaOapov 
aLpLciTOS tovtov 1 eoriv r) x ^ 7 ) T ° ytvofievov TrepLr- 
Tcu/xa- evavrlov re yap rfj rpo(f>fj to TTepLTTOjjia 
fiovXerai etvai Kal rw yXvKet to TriKpov, Kal to 
atfia yXvKV to vyiolvov. (f>avep6v ovv ort ov twos 

30 eveKa, aXX arroKadapfid Iotlv r) X°^V' /ca ^ 
XapieoTaTa Xeyovac twv apxcioov oi <j>doKovres 
aiTiov etvai tov rrXeta) c^rjv xP° vop T ° I 17 ) ^X eiv 
XoX-qv, fiXeiftavTes errl ra ptcovvxa Kal tols eXd(f)OVS' 
TavTa yap a^oAa re Kal tfj ttoXvv xpo vov - 
Kal ra jxr) eajpafieva vtt eKeivcov ort ovk k'xei 

35 x°Xr}V y otov SeXcf)ls Kal KafirjXos, Kal TavTa Tvy- 
xdvei fiaKpopia ovTa. evXoyov yap tt)v tov rfiraTOS 

1 tovtov Peck : TOVT vulg. 



bile elsewhere in the body is a residue or eolliques- 
eenee, so this bile around the liver is a residue 
and serves no purpose — like the sediment pro- 
duced in the stomach and the intestines. I agree 
that occasionally Nature turns even residues to 
use and advantage, but that is no reason for trying 
to discover a purpose in all of them. The truth is 
that some constituents are present for a definite 
purpose, and then many others are present of 
necessity in consequence of these. 

We may say, then, that in animals whose liver is 
healthy in its composition, and in which the blood 
that supplies the liver is sweet, there is either no 
gall-bladder at all by the liver, or else the bile is in 
tiny vessels, or else in some these are present and in 
some not. This is why the livers of gall-bladderless 
animals are, generally, of a good colour and sweet ; 
and in those that have a gall-bladder the part of the 
liver immediately below it is very sweet. But in those 
animals which are formed out of blood which is less 
pure, the bile is the residue of this ; since " residue " 
means that which is the opposite of " food," and 
" bitter " the opposite of " sweet and healthy blood 
is sweet. So it is evident that bile exists for no de- 
finite purpose, but is merely an offscouring. So that 
was an extremely neat remark which we find made 
by some of the old authors, when they say that if you 
have no gall in you your life will be longer. This 
was a reference to animals with uncloven hoofs and 
to deer, which have no gall-bladder, and are long- 
lived. And also, certain other animals are long-lived, 
such as the dolphin and camel, which, though un- 
observed by them, have no gall-bladder. After all, 
the liver is vital and indispensable for all blooded 



677 a 

<f>voLV, iiriKaLpov ovaav /cat dvayhcalav rrdoi tols 
677 b ivalfiOLg ^cools, alrlav etvaL, ttoi&v tlv ovoav ) rod 
t,rjv iXdrra) rj ttXzllo ypovov. /cat to tovtov \xkv rod 
OTrXdyxyov etvat TrepLTTcofxa tolovtov, tcov S' dXXcov 
p,r]8ev6s, /card Xoyov iarlv. rfj fiev yap /capSta 
tolovtov ovSdva TrXrjcrid^eiv olov re ^u/xoV (ovSev 
5 yap Se^erat filaiov TrdOos), tcov §' aXKcov ovSev 
GirXdyyvcov avayKaiov eort rots' l^cools, to S' rjirap 

pLOVOV 8l07T€p KOI TOVTO UVpL^aLV€L 7T€pl aVTO flOVOV . 

dronov re to fir} iravTayov vofxi^ecv, 07tov dv tls 
cf>\eyfAa t) to VTTOGTTjjxa tt\s ko lAias, 77€ptTTCOjLta 
etmt, ofxolcos Se SrjXov otl /cat xoArjV, /cat firj 
io hia<j)ipeaOaL tols tottols. 

Kat 7T€pl fiev ^oA^s", Sta tiv atTtW ra fiev e^et 
tcl 8' ovk e'^et tcov l^cocov, etpTjrat, III. 7rept Se 
fieuevTepLOV /cat €7tl7tX6ov Xolitov etVetV raura yap 

eV TO> TOTTCp TOVTO) /Cat jLt6T(X TtL>l> flOpLCOV €OTt 

15 ' Eort Se to /zev eTTLTrXoov vfirjv rots* /xev oreap 
k)(ovoi OTeaTtbSrjs, tols Se TUfieXrjv 7TLpLeXco8rjs' 
7TOta §' ZotIv €KaT€pa tovtcov, eiprjTai TrpoTepov. 
rjpTTjTai 1 Se to eirlirXoov opLolcos tols t€ [xovokolXlols 
/cat rots* TroAu/cotAtots 1 arro fjieurjs ttjs /cotAta? /card 
r^v VTToyeypafJLiievrjv olov pafirjv iiriyei to re 

20 Aot770v t-^s" /cotAta? /cat to tcw ivTeptov 7TXrjdos 
ofioltos tols ivaLfioLSj ev te tols TTe^ois /cat TOt? 

€Vv8pOLS i^COOLS. 

'H pikv ovv yeveocs i£ dvdyKrjs ovpfiaLveL ToiavTrj 
tov fXopLOV tovtov £rjpov yap /cat vypov p,lyp,aTos 
Oep/^aivopLevov to €.o"%aTov del SepfiaTtoSes ytVerat 

1 rjpKrai SXJYZ. 



animals, and so it is quite reasonable to hold that the 
condition of it controls the length of its owner's life. 
And it is equally reasonable to hold that the liver 
produces a residue such as the bile although none of 
the other viscera does so. Take the heart : no such 
humour as bile could possibly come near the heart, 
because the heart cannot withstand any violent 
affection. Of the other viscera none is indispensable 
to an animal, except the liver only, and that is why 
this phenomenon occurs in connexion with the liver 
exclusively. And it would be absurd to say that 
phlegm and the sediment produced by the stomach 
are residues when found in some places but not in 
others ; and clearly the same applies to bile : its 
locality makes no difference. 

We have now spoken of the gall-bladder, and we 
have shown why some animals have it and why some 
have not. III. It remains to speak of the Mesentery 
and of the Omentum. These are in the same region 
and close to the parts we have just described. 

The Omentum is a membrane, formed of suet Omentum, 
or lard according to the animal in which it is. (We 
have already stated which animals contain suet and 
which lard.) a Whether the animal has one stomach 
or many, the Omentum is always fastened to the 
middle of the stomach, on the line marked on it like a 
seam ; and it covers the rest of the stomach and most 
of the intestines. This is so in all blooded creatures, 
land- and water-animals alike. 

As for the necessary b formation of this part, it 
occurs as follows. When a mixture containing solid 
substance and fluid is warmed up, the surface of 
it always becomes skin-like and membranous ; and 
• At 651 a 26 ff. * See Introd. p. 22. 



Kal vfievtooes, 6 Se tottos ovtos roiavrrjs 7r\r)pr]$ 
25 iarl rpo(f>rjs. ert Se Sta, 7TVKv6rrjra rod vfiivos to 
8ir)6ov{i€vov rfj$ aifiGLTcbSovs rpo<j>r}s avayKaiov 
Xnrapov elvai (tovto yap XeTrrorarov) Kal Sta rrjv 
depfiorrjra ttjv irepl top tottov ov\17T€tt6\L€VOV olvtl 
oapKcoSovs Kal at/xarcoSous* ovordoecog areap yi- 
veoQai Kal 77t/xeA^. rj [xev ovv yeveaig rod €7U- 
30 ttXoov avfifiaivei Kara tov Xoyov rovrov, Kara- 
Xpyjrai S' rj <j>vois avrai irpos rrjv €V7T€iplav rrjs 

TpO(f)rjs } OTTWS paOV 7T€TTT) Kal Q&TTOV TOL £,Cpa T7]V 

Tpo<f>rjv to fiev yap Oepfiov tt€7ttik6v, to Se irlov 

OepjJiOV, TO S' €7TL7tXoOV 7TLOV. Kal StCL TOVT a7TO 
pL€OT]S rjpTTJTai 1 TTjS KO iXlaS , OTl TO €7T€K€LVa 2 [l€pOS 
35 aVfX7T€TT€L TO TTapaKelfieVOV TjTTap. Kal 7T€/H fJL€V 
TOV i7TL7rX6oV €Lp7)TaL. 

IV. To Be KaXovfievov fieoevTepiov eort /xev v\Vf)v y 

StaretVet Se ovvzyks a-no T-fjg twv evrtptov 7raoa- 

678 a Taaecos els ttjv </>Ae/?a TTjv p^eydX-qv Kal ttjv dopTrjv, 

nXrjpeg ov <f>Xe^a)v ttoXXcov Kal ttvkvojv, at TeLvovoiv 

airo Tcov ivrepcov ecs re rrjv fJLtydXrjv (fyXefia Kal tt\v 

dopT-qv. TTjv [lev ovv yeveaiv i£ dvdyK7]$ ovaav 

5 evprjoofiev ofioicog rot? aXXois fioploLg 3 ' Sta Tiva S' 

air lav u77ao^et rots' ivaijiots, <f>avepov ioriv em- 

GK07Tovcriv. iirel yap avayKaiov tcl £a>a Tpo<f>r]v 

Xafifidvetv 6vpa6ev y Kal irdXiv €K TavTrjs ylveoOat 

ttjv luyaTr\v Tpo(j)rjv y e£ rjs rjSrj StaSt'Sorat els ra 

fiopia (tovto Se rot? fiev dvalfMots dvcovvfxov, rot? 8' 

1 ^pKrat EPSUYZ. 
2 eVe/cetra Peck : eV eVeivo vulg. 
3 <toioJtois> fxopiois Ogle : [^toptot?] vy.ta\. Piatt. 



the place where the Omentum is is full of nutriment 
of this very sort. Furthermore, owing to the thick- 
ness of the membrane, that portion of the blood-like 
nutriment which percolates through it must of neces- 
sity be fatty, because that is the finest in texture ; 
and then owing to the heat in that part it will be 
concocted and so become suet or lard instead of some 
fleshy or blood-like substance. This, then, is the way 
in which the formation of the Omentum occurs. 
Nature, however, turns the Omentum to advantage in 
the concoction of the food, so as to enable the animal 
to concoct its food more easily and more quickly ; 
for the Omentum is fat ; fat things are hot, and hot 
things aid concoction. For this reason, too, the 
Omentum is fastened to the middle of the stomach ; 
since as regards that part of the stomach which is 
beyond, the liver which is close by it assists it in 
concoction. So much for the Omentum. 

IV. What is called the Mesentery is also a mem- Mesentery, 
brane ; and it extends continuously from the line of 
extension of the intestines as far as the Great Blood- 
vessel and the Aorta. It is full of blood-vessels, 
which are many in number and closely packed 
together ; and they extend from the intestines as 
far as the Great Blood-vessel and the Aorta. We 
shall find, as with the other parts, that the develop- 
ment and formation of the Mesentery is the result 
of necessity. As for its purpose in the blooded animals, 
that is clear enough to those who consider. Animals 
must of necessity take in nutriment from without ; 
and, again, out of this the "ultimate nutriment" 
has to be made ; and from this store the supply is 
distributed directly to the parts of the body. (In 
blooded animals this is called blood ; there is no 



678 a 

10 eVat/xot? at/xa /caAetTat), Set ti elvai hi ov els ra$ 
<f)Xefias €K tt]s KoiXlas olov hid pit,cov TropevaeTai r) 
Tpocfirj. ra fiev ovv <f>vra ras pit,as k'xei els ttjv yrjv 
(eKeiOev yap Aa/x/?dVet ttjv rpo^rjv), tols he ^coois rj 
KoiXia kcll 7) tcov evTepcov hvvafxis yrj Iotiv, e£ rjs 
Set Xafifidveiv tj\v rpo^rjv hioTrep rj rod fieuev- 

15 replov envois eWtV, olov pl^as e^ovaa ra? St' auras' 1 
tbXefias* ov [lev ovv ere/ca to yLeoevrepiov eariv, 
eiprjTai* rtVa Se rpoirov Aa/i/3dVet tt)v Tpo^rjv, /cat 
ttcos eluepye.T<xi hid tcov (f>Xefitov airo rrjs ecr^ar^s 2 
Tpo<f>rjs els ra fxopia Trdvra 3 to hiahihofievov els rds 
tpXefias, ev rocs Trepl ttjv yiveoiv tcov i^cptov Xe)(6r)- 

20 oerai Kal ttjv rpo<f>rjv. 

Td (lev ovv eVatjua tcov t^cocov ttcos e^et /xe'^'pt rcbv 
hicopiofxevtov fxopicov, Kal hid rivas atrtas 1 , eiprjrai' 
irepi he tcov els ttjv yeveuiv ovvTeXovvTCOv , ois hoKel 
hia<f>epeiv to OrjXv rod dppevos, e\6pLevov [lev e'ort 

25 /cat Xoiuov twv elpTjiievajv aXX eireihrj Trepl yeve- 
ceco$ XeKTeoVy dpfioTTOv eort Kal Trepl tovtcov ev Tjj 
Trepl eKelvcov Oecopla hieXOeiv. 

V. Ta Se KaXovf.ieva /xaAa/aa Kal /xaAa/coorpa/ca 
TToXXrjv exei -rrpos raura hiachopav evdvs yap ttjv 
tcov OTrXdyyycov drraaav ovk e\ei c/)vgiv. o^olcos S* 
so ouSe tcov aXXcov dvaificov ovhev. euTi he hvo yevrj 
Xonrd tcov dvaificov, ra t dorpa/coSeo/xa /cat to tcov 
evTopLwv yevos. e'£ ov yap ovveOTrjKev rj tcov 
OTrXdyyycov envois, ovhev tovtcov e\ei at/xa, Std to 

1 avrrjs Peck : avrrjs vulg. 
* £ox(LT7]s Peck : eloiovaqs vulg. 
3 -nciVTa Ogle : ravra vulg. : om. Z. 


special name for it in the others.) Now there must 
be some passage or passages (as it might be roots) 
through which this nutriment shall pass from the 
stomach to the blood-vessels. The roots of plants 
are of course in the ground, because that is the 
source from which plants get their nutriment. For 
an animal, the stomach and the intestines correspond 
to the ground, the place from which the nutriment 
has to be derived. And the Mesentery exists to 
contain these vessels, corresponding to roots ; they 
pass through the inside of it. This completes my 
account of its Final Cause. As for the means by 
which the nutriment is taken up, and the way in 
which that portion of the ultimate nutriment which 
is distributed into the blood-vessels reaches all the 
parts of the body through them, these points will 
be dealt with in the treatises on the Generation of 
Animals and on Nutrition. 

I have now described the blooded animals as far 
as concerns the parts that have been dealt with, and 
also the causes that are responsible. It remains, 
and would follow after this, to speak of the organs 
of generation, by which male and female are dis- 
tinguished. But as we shall have to deal with 
generation itself, it is more appropriate to speak of 
these organs in our consideration of that subject. 

V. The animals called Cephalopods and Crustacea ™™ N o A F L 
are very different from the blooded ones. First of all, bloodless 
they have no visceral structure at all. This is true animals. 
of all the bloodless creatures, in which are included 
beside Cephalopods and Crustacea two other groups, 
the Tcstacea and the Insects. This is because none 
of them has blood, which is the material out of which 
l 315 


rfjs ovalag avrwv elval tl tolovtov irdOog [auras'] 1, 
otl yap iuTi ra fiev evaifia tol S' aratfia, ev to) 

35 Xoyco ivvirdp^ei to) opi^ovTi TTjv ovolav avrcov. en 
S' Sv eveKev exovoi ra GTrXdyx^a evaifxa tojv 
^(LojVy ovBev virdp^eL tols tolovtols' ovt€ yap 
€78 b <j)\ej3as tyovaiv ovre kvotlv ovt dvarrveovaLV, dXXd 
fiovov dvayKalov e^etv avrois to dvdXoyov rfj Kap- 
Bia' to yap aluQrjTiKov fax*) 1 * Ka ^ T ° T V$ fa^S a *" 
tlov {eV) 2 dpxfj tlvl rwv jjLopiwv Kal tov craj/xaTO? 
vrrapx^ tt&ol tols ^ojols. ra Be. TTpos tt)v Tpocf)r]v 
5 fiopia €%€t Kal ravra i£ dvdyKTjs ixavra' 01 Be 
TpouoL Bia<f>epovoi Bid rovg tottovs iv ois Xafi- 
fidvovai ttjv rpo<f)rfv. 

"E^ouat Be ra [lev /xaAa/aa rrepl to KaXovfievov 
arofia Bvo 6B6vTas s Kal iv ra> orofiaTi dvrl yXcor- 
T7]s aapK&oes tl s <L Kpivovat ttjv iv rots eBevTols 
rjBovrjV. ofjiolws Be Kal rd fxaXaKoarpaKa tovtols 

10 rovs 7rpd)TOV$ ohovras e^et Kal to dvdXoyov rfj 
yXcorrr} crapKcoSes. en Be Kal ra darpaKoBepfxa 
navra to tolovtov e^et jxopiov Bid ttjv avTrjv alrlav 
TOls ivaifJLOLS, TTpOS TTjV TTjS Tpocfrrjs atoOrjoiv. 
oyLolcas Be Kal ra evTOfia ra piev rrjv i^iovoav im- 


15 yevos Kal to tojv (jlvlqjv, cioTrep etp^rat Kal irpo- 
Tepov 60a Be firj ioTiv ipLTrpooOoKevrpa, iv tco 


pLvpfJLrjKwv yevos Kal ei rt tolovtov erepov. SBovTas 
Be ra fiev e'xei tovtwv, aXXoLOTepovs Be, KaOdirep 
1 avTrjs seclusi. 3 iv supplevit Th. 

a See Introduction, pp. 26 ff. 

6 These teeth are the two halves of what might be com- 
pared to a beak. 


viscera are made ; and the reason for this is that a 
condition of this sort is part of their being : the fact 
that some animals are blooded and some bloodless 
will be found to be included in the logos a which 
defines their being. Further, we shall see that none 
of those purposes for whose sake blooded animals 
have viscera operate in these other creatures : they 
have no blood-vessels and no bladder, they do not 
breathe : the only organ they must necessarily have 
is the counterpart of the heart, since the sensitive 
part of the Soul and the original cause of life is always 
situated in some place which rules the body and its 
parts. Also, they all have of necessity the parts 
adapted for dealing with food and nutrition ; but the 
manner of these varies according to the places where 
they take their food. 

The Cephalopods have two teeth around what is 
called their mouth b ; and inside the mouth, instead of 
a tongue, they have a fleshy object, by means of 
which they discriminate the savour of things to eat. 
Likewise, the Crustacea have these front teeth and 
the fleshy counterpart of the tongue. The Testacea 
all have this latter part, too, for the same reason that 
blooded animals have a tongue, viz. to perceive the 
taste of the food they eat. Similarly, too, the Insects 
have, some of them, a proboscis which comes out 
from the mouth, as with the Bees and Flies (this has 
been mentioned earlier c ) ; and the ones which have no 
sharp protrusion in front have a part such as this 
inside the mouth, as Ants, and the like. Some of 
these creatures have teeth, though somewhat differ- 
ent from ordinary teeth (as the Flies,** and Bees) ; 

c At 661 a 21 ; cf. Hist. An. 528 b 28. # 
d Or " Ants " (translating Meyer's emendation). 



678 b 

to re tow fJLVicov Kai to tojv fxeAtrrajv yevog, ra o 
20 ovk e'x^t, oaa vypa xP^) Tai T fj Tpo(f>fj* 7roXXd yap 
to>v ivTofiajv ov rpo(f)rjg e^et X^P iV T °vs oSovras 
dXX dXKrjs. 

Ttov 8' oarpaKohipficov ra /xeV, aJoTrep iXi-^dt] Kai 
iv tols kclt* dpxas Xoyois, ttjv KaXovpiivrjv e^et 
yXwrrav icrxvpdv, ol 8e ko^Aoc /<at dSovTa? Svo, 
25 KaOdnep ra piaXaKocrTpaKa. pierd 8e to OTopia tols 
pcaXaKLOLS iuTi UTopLa-^os ptaKpos, tovtov 8* 

pL€VOS 7Tp6\of$OS OLOS 7T€p Tots SpVLGLV, €tTO, GVV€)(7]S 
KOlXla, KOLL T0LVT7JS i\6p€.VOV €VT€pOV dnXoVV ^XP l 

Trjs i£68ov. Tat? piev ovv GrprriaLs Kai tols ttoXv- 

7TOGLV OpiOld Kai ToTs CT^/XaCTl KOL Tjj d(j)fj T<X 77601 

30 rfjv KoiXiav Tat? 8e KaXovpLevais tcvQlol Svo piiv 
opioids at /cotAtcoSet? eiatv vTroSo^al, tjttov Se 
7TpoXof$d>h-qs rj eTepa, Kai tols oxqp.aaiv eKelvwv 
8ia<f)4povoL hid to Kai to ocbpia tt&v €k pbaXaKOj- 
Tepas avvecTTavaL uapKos. 

Tatrra 8' e^et tcz piopia tovtov tov Tponov Sta 
tt)v avTTjv atTtW djoirep Kai ol opviOes' ovhe yap 

35 tovtcov ovSiv eV8e^€Tat AeatWiv ttjv Tpo^rjv, SioVep 

6 7Tp6XopOS ioTL 7Tp6 T7)S KOlXLaS . 

Upds fiorjOeiav 8e /cat G(x>Ti}plav e^et raura tov 

679 a KaXovpevov OoXdv iv \ltoovl vpLevwhec irpoG7T€<j)v- 

kotl, 2 tt]v e^oSov €\ovtl Kai to iripas fjTrep d<f>iaoi 
to 7repiTT(x>pa tt)s KoiXias KaTa tov KaXovpievov 
avXov ovtos 8' egtlv iv tols v7ttlols. e^et piiv ovv 
5 irdvTa Ta pLaXaKLa tovto to pcopLov t'Stov, pidXLOTa 
8' rj crr]7TLa Kai ttXclgtov oTav yap (f>op7]9woL Kai 

1 hviojv] [ivitov l^toov EY : fjcvpfx^Kcov Meyer. 

2 TTpoane^vKOTL Ogle : Ttpoan^VKora vugl. 



others have no teeth at all : these are the creatures 
whose food is fluid. Indeed, in many of the insects 
the purpose of the teeth is not mastication of food at 
all, but for use as weapons. 

Of the Testacea, as we stated in the opening treat- 
ise, some have a very strong tongue (so-called) ; and 
the Sea-snails actually have two teeth as well, like the 
Crustacea. In the Cephalopods there is a long gullet 
next after the mouth, and contiguous to that is a 
crop like a bird's. Continuous with this is the 
stomach, then immediately the intestine, which is 
simple and reaches to the vent. In the Sepias and 
Octopuses these parts round the stomach are similar 
both in shape and in consistency. The creatures called 
Calamaries, like the others, have the two gastric 
receptacles, & but the first of them is less like a crop ; 
and they differ in shape from the organs of the 
previous classes, and that is because their bodies are 
composed of softer flesh throughout. 

These creatures have these parts arranged in this 
way for the same reason that birds have them : they, 
like birds, are unable to grind down their food ; hence 
the crop is placed before the stomach. 

The Cephalopods, for the sake of self-defence and 
self-preservation, have what is called their Ink. This 
is contained in a membranous bag which is attached 
to the body, and comes to an end in an outlet where 
the residue from the stomach is discharged by the so- 
called funnel. This is on the under side of the body. 
All the Cephalopods have this peculiar part, but it is 
most remarkable in the Sepia, as well as the largest 
in size. When the Sepia is frightened and in terror, 

« At Hist. An. 528 b 30 ff. 
b Viz. the crop and the stomach. 



$e(acooiv } olov <f>pdyjia irpo rod acbfiaros iroiovvrai 
rrjv tov vypov fieXavlav Kal BoXojgiv. at fxev ovv 

T€v9toe$ KOLL TToXviTOOeS e.X 0V(JlV dvwBeV TOV 8o\6v 

iirl rfj {jlvtlol fidXXov, rj oe orjTrla Trpos rfj KOtXla 
10 Kara)' 7rXeluj yap e^et Std to xpyjodai fiaXXov. 
tovto 8* avrfj GVfipalvet Sid to irpooyeiov jiev etvai 
tov filov avrfjs, fxrj £x eiv ^ clXXtjv fiotfOeiav, wotrep 
6 TToXvnovs ras rrXeKrdvas e^et XPV ^ ^ /ca ^ T V V 
rod ^oaj^aTO? fierafioX-qv, rj avfifiatveL avTw, 
coanep Kal r) rod doXov TTpozois, Sid SeiAiav. r) oe 
16 T€v6ls ireXdyiov ion tovtojv fiovov. TrXeloj fiev ovv 
e^ei V (J1 } 7rLa 7ra / )( i toOto tov OoXoVy KarcoOev Se Sid 
to irXeia)' pdoiov yap TrpoteoOaL Kal uoppayQev dno 
tov nXelovos. ylverat Se [o OoXos], 1 Kaddrrep to?s 
opVLGLV vrroarrjfjia to XevKov errl tov TTepirrwpLaTOs 
yecaSes, ovtoj Kal tovtois 6 QoXos oia to [xrjSe TavT 
20 €%€iv kvotiv aTTOKplverai yap to yeojSeGTarov els 
avrov, Kal Tjj arjTTLa irXeiGrov Sid to TrXeiorov ex €LV 
ye<2>Ses\ Grjfxelov Se to gtjttlov tolovtov ov tovto 
yap 6 fxev ttoXvttovs ovk ex el > a ^ ^ TevOlSes X ov ~ 
SpwSes Kal Xeirrov. (Si* rjv S* alriav rd fiev ovk 
e^ei Ta S' e^et, Kal ttolov ti tovtojv exec eKarepov, 
eLprjrai. 2 ) 

25 ^Avaijjiojv 8' ovtcov Kal Sid tovto Kareifjvyfievwv 
Kal <f>ofir)TiK(x)V } coGTrep evtocs orav SeLoojGiv rj 
KOiAia TapaTT€Tat, tols 8' €K tt}s kvgt€ojs pel 

7T€ptTT(JL)GlS, Kal TOVTOIS TOVTO GVjJij3alv€L fJL€V i£ 

1 [6 6oX6s] seel us i : 6 om. P. 
2 €tpr)Tai TTporepov P. 

° The mytis, which is the same as the mecon, is an excretory 
organ, and corresponds to the liver. See below, 679 b 11. 
b Cf. above, 676 a 32. 



it produces this blackness and muddiness in the 
water, as it were a shield held in front of the body. 
Now the Calamaries and Octopuses have this ink-bag 
in the upper region of the body, quite near the mytis a \ 
whereas in the Sepia it is lower down, against the 
stomach, since it has a larger supply because it uses 
it more. This circumstance is clue (1) to its living 
near the land and (2) to its having no other means of 
defence — nothing like the Octopus, for instance, which 
has its twining feet, which are useful for this purpose ; 
it can also change its colour, and it does so (just as 
the Sepia emits its ink) when put in fear. Of all 
these, only the Calamary lives well out at sea and gets 
protection thereby. Hence, compared with it, the 
Sepia has a larger supply of ink ; and because this is 
larger, it is lower in the body, as it is easy for it to be 
emitted even to a considerable distance when the 
supply is great. The ink is earthy in its nature, like 
the white deposit on the excrement of birds, and it is 
produced by these creatures for the same reason — 
they, like birds, have no urinary bladder b ; so the 
earthiest matter is excreted into this ink, especially 
in the Sepia, for the Sepia contains an exceptionally 
large amount of earthy matter. An indication of 
this is its bone, which is earthy. The Octopuses do 
not have this bone, and in the Calamary it is cartila- 
ginous and slight. (We have said why some of these 
animals have this part and why some have not, and 
what in each case its character is.) 

These animals, as they have no blood, are cold and 
liable to take fright. While in some other animals 
fear causes a disturbance of the stomach, and in some 
the discharge of residue from the bladder, in these 
creatures its effect is to make them discharge their 



679 a 

avayKTjs d<f>iivai Sia heiXiav, tuoTrep ck Kvcrrecos 


80 TcofJLOLTL KaraxprjTai rrpos fiorjOeiav Kal acorrjptav 

"E^oucn 8e /cat rd /xaAa/<dor pcLKa , rd re Kapa- 

fioeiSrj Kol 01 KdpKLVOL, 8vO fieV oSoVTOLS TOVS 

rrpcuTovs, Kal [lera^v rr)v odpKa rr)v yXtoacroeiSrj , 

<J)G7T€p €LprjT<lL Kal TTpOTtpOV, evOvS 8' exOfieVOV rod 

OTOjJLGiTos arofjiaxov jJLLKpov Kara fieyeOos rcov 
35 acofidrcov [rd fiec^a) 7Tp6g rd eXdrrco^" rovrov 8e 
KOiXlav ixojJi€vr]v s ecj>* rjs ot re Kapafioi Kal evioi 
rcov KapKivwv ohovras k'xovoiv erepovs hid rd rovs 
679 b avco jJLTj 8iaipelv iKavcoSy and 8e rrjs KoiXlas evrepov 
drrXovv /ccrr' ev6v p-^XP 1 n P^ Tr ) v %£o8ov rod 

7T€pLTTO)fiaTO$ . 

"E^ei 8e Kal rwv oorpaKoheppwv eKaarov ravra 
rd fiopia, rd fiev 8i7)pdpcofjLt'va pL&XAov rd 8' rjrrov 
ev Se rols fiei^ooi 8ia8rjX6repd eonv eKaara rov- 
5 rcov. ol fiev ovv /cd^Aoi Kal 686vras k'xovoi gkXt]- 
povs Kal d^eis, coarrep eiprjrai irporepov, Kal rd 
ixera^v oapKcoheg 6{ioicos rois /xaAa/aois" Kal fiaXa- 
KoarpaKOiSj Kal rr)v 7rpo/3o<7/a'8a, Kaddrrep eip-qrai, 
(jiera^v Kevrpov Kal yXcorrrjs, rod 8e aropiaros 
exopuevov ocov 6pviBco8r) rivd rrpoXofiov, rovrov 8' 
10 ixdfJLtvov arofiaxov rovrov 8' k'xerai r) KoiXla, ev fj 
rj KaXovpLevrj i±t]klov s aft rjs avvex^s eonv evrepov 
aTrXrjv rr)v apx^v k\ov and rrjs firjKcovos' eon yap 
iv naai rots oarpaKrjpots neptrrcofia rovro rd 
vara Sokovv elvai iStvhijjiov. k^ei 8' opioLcos rco 


1 seclusit Rackham. 


ink ; and though this is an effect due to necessity, 
like the discharge of urine in the others, yet Nature 
makes good use of this residue at the same time 
for the animal s defence and preservation. 

The Crustacea as well, that is, both the Crabs and 
the Caraboids, have the two front teeth, and between 
the teeth they have the tongue-like flesh, as has 
already been stated a ; and immediately next to the 
mouth they have a gullet which is quite small com- 
pared with the animal's size ; and immediately after 
that the stomach ; and on this the Carabi and some 
of the Crabs have another set of teeth, since the 
upper ones do not masticate the food sufficiently. 
From the stomach a simply formed intestine runs 
straight to the vent where residues are discharged. 

These parts are present in every one of the Testacea 
as well, more distinct in some, less in others. They 
are more clearly marked in the larger animals. 
Take the Sea-snails. These have (1) as stated al- 
ready, the teeth, which are hard and sharp, (2) the 
fleshy object in between them, similarly to the 
Crustacea and Cephalopods ; (3) the proboscis, as 
already mentioned, 6 something between a sting and 
a tongue ; (4) immediately after the mouth is a sort 
of bird's crop, and (5) after that the gullet ; (6) con- 
tinuous with that is the stomach, and (7) in the 
stomach is what is known as the mecon ', and (8) at- 
taching to this is an intestine : this intestine begins 
directly from the mecon. This residue (the mecon) 
appears to be the most tasty piece in all the Testacea. 
The other creatures that have spiral shells (e.g. the 

a At 67S b 10. 
6 At 661 a 15 ff. 
c The hepatopancreas or liver ; see above, 679 a 9. 

l2 323 


679 b 

15 koxXco koX raXXa to, arpofipcoSrj, olov 7rop<f>vpai 


"Ecru oe yivt) Kal zlhrj ttoXXol rcov oarpaKO- 
Sepfiwv ra (lev yap arpoji^cLhrj iorlv, cboirep ra 
vvv elprjfjieva, ra Se hiOvpa, ra he fiovoOvpa. rporrov 
he rcva Kal ra arpofjipwhr] hiOvpois eoiKev exei yap 
eiriirr\)y\xar eirl rw <f>avepcp rrjs crapKos rrdvra ra 
20 roiavra eK yeverrjs, olov at re iropfyvpai Kal 
KrjpvKes Kal ol vqpeirai Kal ttolv to roiovrov yevo$ } 
TTpos ftorjOeiav fj yap firj TTpofiefiXrjrai ro ourpaKov, 
pdhiov ravrrj fiXdrTreoOai vtto rcov dvpadev rrpou- 


7T€^>VK€vai aw^erai rco irpaves ^X €lv T ° ourpaKov, 
25 Kal yiverai dXXorpico ^>pdy\xari rpoirov riva hi- 
Qvpov, olov at KaXovp.evai Xerrdhes' rd he hiOvpa, 
olov Kreves Kal fives , ra) wvdyeiv , ra he arpofi^cohrj 
TOVTtp rep eTTiKaXviipLariy cooTrep hiOvpa yivojieva eK 
fiovodvpcov. 6 8' £){ivos {idXiara irdvrojv dXecopav 
e^er kvkXco yap to oorpaKov avvrjpe<f>e? Kal Ke- 
80 xapaKcofiivov Tat? aKavdais, ihiov 8' e^et rcov 
oarpaKohepjicov rovro, KaOdirep eipr\rai irporepov. 
Twv he fiaXaKoorp a/cco v Kal rcov oGTpaKohepficov 

GVV€CTT7]K€V Tj <f)VGlS TOt? /XaAa/CtOt? dvTlK€lfJL€Va)S' 

tois jikv yap e^co to aapKcohes, roi? S' evros, €Kt6? 
e to yecooes. o o ex^os ovoev e^et vapKcooes . 
35 Udvra fiev ovv €X €L > f<a9a7rep eiprjrai, Kal TaAAa 
ra ocrrpaKoBepfia arofia re Kal to yXcorroeiheg K'at 
KoiXlav Kal rod Trepirrcbjxaros rrjv e^ohov, hiacbepei 

a The operculum. 



Purpuras and the Whelks) are similar to the Sea- 
snails in structure. 

There are very many genera and species of Tes- 
tacea. Some have spiral shells, like the ones just 
mentioned ; some are bivalves, some univalves. In 
a way, the spiral shells resemble the bivalves, as they 
have, all of them, from birth, a covering over the 
exposed part of their flesh, e.g. the Purpuras, the 
Whelks, the Nerites, and the whole tribe of them. 
This covering serves as a protection ; for in any place 
where the animal has no shell to protect it, it could 
quite easily be injured by the impact of external 
objects. The univalves' means of preservation is this: 
they cling to some object, and have their shell on the 
upper side ; so they become in a way bivalves in 
virtue of the borrowed protection afforded by the 
object to which they cling. Example, the Limpets. 
The bivalves proper (e.g. Scallops and Mussels) get 
their protection by closing themselves up ; the spiral- 
shelled creatures by the covering I mentioned, which, 
as it were, turns them from univalves into bivalves. 
The Sea-urchin has a better defence system than any 
of them : he has a good thick shell all round him, 
fortified with a palisade of spines. As I stated pre- 
viously, the Sea-urchin is the only one of the Testacea 
which possesses this peculiarity. 

The natural structure of the Crustacea and of the 
Testacea is the reverse of that of the Cephalopods. 
The latter have their fleshy part outside, the former 
have the earthy part outside and the fleshy inside. 
The Sea-urchin, however, has no fleshy part at all. 

All these parts, as described — mouth, tongue-like 
object, stomach, vent for the residue — are present 
in the rest of the Testacea too, but they differ in 



680 a he rfj 9eaei Kal tols fieyeOeaiv. ov he. rpoTrov k'yet 


t^wa OewpetaOw Kal Ik twv avarofxwv tol fiev yap 
to) Xoyw tol he npos ttjv oi/jlv atfTwv aa^rjvL^eiv hel 

'ISt'co? 8' k'xovGL twv ogt paKohep\xwv 01 t* exivoi 
6 Kal to twv KaXovfievwv Tt]6vwv yevos. k'xovai 8' ol 
€)(Zvoi ohovTas fiev irevTe Kal fxeTa^v to aapKwhes, 


rroXXd hirjprjfievrjv, wairepavei ttoXXols rod t,wov 
KoiXias exovTog. Kex<*)pLO yievai jiev yap elai Kal 

10 7rXrjpeis TrepiTTWfiaTOS, e£ ivos 8' T]pTH]VTai tov 
GTOfjLa)(ov Kal TeXevTwoL irpos p*Lav e^ohov tt)v tov 
TrepiTTcojiaTOS. Trapa he tt]v KoiXlav crapKwhes p*kv 
ovhev €xovcnv f wuirep etprjTaL, tol he KaXov\xeva wd 
rrXeiw tov aptOjiov ev vpLevi x°°P^ eKacrTOV, /cat 
kvkXw oltto tov GTOjxaTOs jieXav* aVra hieoTTapfiiva 

is xvhrjv, avwvvfjia. ovtwv he -nXeiovwv yevwv (ov yap 
ev ethog twv ex^wv udvTWV Igtl) irdvTes fJiev k'xovai 
ravTa tol piopia, aXX ovk ehwhipia irdvTes tol 
KaXovf-teva wd y Kal fiiKpd rrdfjiTTav e£w twv ein~ 
TroXa^ovTWV. oXws he tovto Kal nepl raAAa ov[i- 

20 fiefirjKe to. SaTpaKohepfJia- Kal ydp at adpices oi>x 
ofJLolwg ehwhifioi ttolvtwv, Kal to TrepLTTWjJLa, rj 
KaXovjievrj fjbrjKwv, evtwv fxev ehwhifjios evlwv 8' ovk 
ehwhipios. eoTi he. tols OTpojifiwheGiv ev Tjj eXu<7) 

° Hist. An. 528 b 10 ff. 

b This seems to imply that diagrams or illustrations accom- 
panied the treatises. 

c These form what is compared to a lantern at Hist. An. 
531 a 5, hence the name, ** lantern of Aristotle." 


their position and size. For the details of these, eon- 
suit the Researches upon Animals 0, and the Dissections. 
Some points are better explained by inspection b than 
in words. 

The Sea-urchin and the genus of Ascidians are 
peculiar among the Testacea. The Sea-urchin has 
five teeth, c and between them it has the fleshy sub- 
stance (the same as in all the above-mentioned 
creatures) ; after that, the gullet, after that, the 
stomach, which is divided into several compartments, 
so that the animal seems to have several stomachs. 
But although they are separated from each other and 
are full of residue, they all spring from the gullet and 
they all terminate in the residual vent. Apart from 
the stomach, these creatures contain no fleshy snb- 
stanee, as I have said. They have, however, what 
are called ova a ; there are several of them and each 
is in a separate membrane ; and scattered at random 
round the body, beginning from the mouth, are 
certain black objects/ which have no name. There 
are several kinds of Sea-urchin, and in all of them 
these parts are present. Not all, however, have 
edible / ova, and, except in the common 3 varieties, 
they are quite small. There is a similar distinction 
among the other Testaeea : the flesh is not equally 
edible in all of them, and in some of them the residue 
(the so-ealled mecon) is edible, in others not. In the 
spiral shells, the mecon is in the spiral, in univalves 

d These are really ovaries (or testes) : gonads. 

* These may be the ambulacral vesicles, but the identifica- 
tion is not certain. 

' See the story of the Spartan in Athenaeus iii. 41. 

g The word translated " common " may mean ** living near 
the surface." 



680 a 

TOVTO s TOLS Se fJLOVo9vpOL$ iv TO) 7Tv9fl€Vl f OLOV TOLS 

Xeir&oi) tols Se SiOvpois Trpds rfj uvva<f>ff to S* coov 
25 KaXovfievov iv tols Sef tot?, iv Se tols em Bdrepa rj 
etjoSos tov TTepiTTcopLaros rots SiBvpots. /caAetTat 


ivTiv olov tols ivalpLOLSy otolv evdy]vajuLv, r) ttl6t7]$. 


ivLCLVTov iv ots evdy)vovGiv s ev Te tco eapt /cat 
fieTorrwpcp' iv ydp tco i/w^et /cat Tat? aAe'at? tto- 

30 vovai irdvra to. ocrrpaKoSepfia, /cat cfripeiv ov 
Svvavr at Tas VTrepfioXds . cn?/xetoi> Se to gv\Jl$<xlvov 
eVt to)v iylvojv evOvs Te ydp yLvofxevoi exovaL /cat 
iv tols TTavcreXrjvoLs fJL&XXov y ov Sta to vifxeadat, 
Kaddircp TLves otovTat pL&XAov, dXXd Sta to aAeetvo- 
T€pas etVat Tas vvktcls Sta to epeos Trjs GeXrjvys. 

35 Suaptya ydp ovto. Sta to dVat/xa etvat Se'ovTat dXe'as'. 
Sto /cat iv to) dipei fxaXXov ttclvtolxov evOrjvovaiv, 
680b ttXtjv ot iv to) Hvppaia) cup wrap e/cavoi S' oi>x 
TjTTOV tov xet/xaVos" atVtov Se to vofirjs eviropelv 
tot€ [laXXov, aTToXeiTTOvTWv tojv lyBvcov tovs to- 
7tovs /caTa TavTt]v TTjv topav. 
"E^otiat S s ot i^ivoL TrdvTes taa Te tco dpidpLtp Ta 
5 d)d /cat 77eptTTa* irivTe ydp iyp VGlv > togovtovs Se 
/cat toi)? ooovtols /cat Tas 1 /cotAt'as 1 . atVtov S* 6Vt to 
ojov eVrt, Kaddrrep etpTjTat TTpoTepov, ovk coov dXXd 
tov £a>ou evTpo(/)La. ytVeTat Se tovto eVt 0aVepa 

° This is true of the sea-urchins in the Red Sea, though not 
of the Mediterranean ones. The former have a cycle corre- 
sponding exactly to that of the moon. The five roes, ovaries, or 
testes are large and swollen during the week preceding each 
of the summer full moons, and the spawning of the eggs 
takes place during the few days before and after full moon. 
For a most interesting discussion of this and kindred matters 


(like limpets) it is in the tip ; in bivalves it is near 
the hinge. In the bivalves the so-called ovum is on 
the right-hand side, and the residual vent on the left. 
" Ovum " is a misnomer ; actually it corresponds to 
fat in blooded creatures when they are in good con- 
dition ; and that is why it appears only in spring and 
autumn, which are the seasons when they are in good 
condition. In great cold and great heat all the 
Testacea are hard put to it ; they cannot endure in- 
ordinate temperatures. The behaviour of the Sea- 
urchins is a good illustration of this : they have ova 
in them as soon as they are born, and at the time of 
full moon these increase in size a ; and this is not, as 
some think, because the creatures eat more then, but 
because the nights are warmer owing to the moon- 
light. These creatures have need of the heat because 
they are bloodless and therefore adversely affected 
by cold. That is why they are in better condition 
during the summer, and this is true of them in all 
localities except the strait of Pyrrha, & where they 
flourish equally well in winter, and the reason for this 
is that in winter they have a more plentiful supply of 
foodstuff, due to the fish leaving the district at that 

The Sea-urchins all have the same number of ova — 
an odd number, five, identical with the number of 
teeth and stomachs which they have. This is ac- 
counted for by the " ovum " not being really an ovum 
(as I said before) but simply a result of good nourish- 
ment. The " ovum " is found in Oysters too, though 

see H. M. Fox, Selene, especially pp. 35 ff., and id. Proc. 
Roy. Soc. 1923, 95, 523. 

b In Lesbos, leading to the lagoon, one of Aristotle's 
favourite hunting-grounds: see Hist. An. 544 a 21 (sea- 
urchin), 548 a 9, 603 a 21, 621 b 12. Cf. Gen. An. 763 b 2. 



jjtovov iv rots SoTpeoLs, to KaXovfievov d)6v. tolvto 
Be tovto ion /cat to iv tois envois, inel tolvvv 
10 earl o<f)aipoeL?)r}s 6 ex}VOS 3 Kal oi>x cooirep errl tcov 
dXXcov ooTpecov tov awfiaros kvkXos els, 6 8' expos' 


(ocftaipoeihrjs yap), dvdyKTj Kal to chov Sfiolcos ex^tv 
ov yap ioTiv, cooirep toi? a'AAot?, to kvkXco dv- 
ojjioiov iv fieacp yap f) KetfraXrj iraoiv avrols, rco 8* 

15 aVa» to toiovtov fiopiov. dXXd firjv ouSe ovvex^s 
olov t elvat to ojoV — ou8e yap tols dXXois- — aAA' iirl 
Odrepa tov kvkXov jxovov. dvdyKT] towvv, irrel 
tovto fiev arrdvTCOv kolvov 9 lSlov 8' e/cetVou elvat 
to ocofia ocftaLpoetSes , firj elvai dpTca Ta cod. koltcx 
hidpi€Tpov yap av rjv t Sta to ofiolcos Selv ex €lv T ° 

20 evdev Kal evdeVy el r\v dpTia [/cat /caTa SidfieTpov] 1 - 
ovtcos 8* ixdvTOJV en - ' d\ichoTepa dv tov kvkXov 
elxov to coov. tovto 8' ovk rjv ouS' eVt tcov dXXcov 
ooTpecov eirl ddWepa yap ttjs irepichepeias exovoi TO, 
ooTpea Kal 01 KTeves to toiovtov fiopiov. dvdyKT) 

TOIVVV Tpla Tj 7T€VT€ €Ll'ai Tj dXXoV TIV dpiOfJLOV 

25 TreptTTdV. el jiev ovv Tpta et^e, iroppco Xlav (aV) 2 
rjv, el Se TrXelco tcov nevTe, ovvex^S dv tovtcov 8e 
to fiev ov fieXTLov, to 8' ovk evSexdfievov . dvdyKrj 
apa TrivT avTOvg ex €LV TC * 4*®" 

Ata TTjv avTrjv 8* ahlav Kal rj KotXla TOiavTi) 
ecr^taTat Kal to tcov SSovtcov tooovtov eoTi irXrjdos. 
(LKaoTOV yap tcov chcbvy olov ocofid ti tov t^coov ov > 


1 secludenda. 2 (av) Ogle. 

3 Koihlas Ogle : £a>i}s vulg. 



on one side of the body only ; it is the same as that of 
the Sea-urchin. Now the Sea-urchin is spherical, 
and is not just one flat disk like the Oysters ; thus, 
being spherical, it is not different shapes in different 
directions, but equiform in all directions ; hence of 
necessity its " ovum " is correspondingly arranged, 
since this creature's perimeter is not, as in the others, 
non-equiform a : they all have their head in the 
centre, whereas the Sea-urchin's is at the top. 
Yet even so the <( ovum " cannot be continuous, 
since no other of the Testacea has it thus ; it 
is always on one side of the disk only. Hence, 
since this is a common property of all species 
of Testacea, and the Sea-urchin is peculiar in having 
a spherical shape, the result follows of necessity that 
the Sea-urchins cannot have an even number of ova. 
If they were even, they would have to be arranged in 
diametrically opposite positions, because both sides 
would have to be alike, and then there would be ova 
on both sides of the circumference ; but this arrange- 
ment is not found in any of the other Ostreae ; both 
Oysters and Scallops have ova on one side only of 
their circumference. Therefore there must be three, 
or five, or some other odd number of ova in the Sea- 
urchin. If there were three, they would be too far 
apart ; if more than five, they would be quite con- 
tinuous ; the former would not subserve a good 
purpose, the latter is impossible. Therefore the 
Sea-urchin must of necessity have five ova. 

For the same cause the creature's stomach is cloven 
into five and it has five teeth. Each of the ova, being, 
as it were, a body belonging to the creature, must 
conform to the general character of the stomach, 

° That is, it is circular in all planes, not in one only. 



680 b » \ \ 

avayKaZov evTevBev yap r) avtjrjats* /uS? yap 

ovorjs rj rroppa) av rjaav, rj trav av /carel^e to kvtos, 
ware Kal SvGKtvrjrov elvai tov exivov Kal fir) TrXrj- 
povodai rrjg rpo(f>rjs to dyyetov ttIvtc 8' ovtcov 
twv hiaXeipLpiarojv dvdyKrj TTpos eVacrTO) ouow 
35 Trevraxfl SirjprjaOai. Sid rr)v avrrjv 8' alrlav Kal 
to tu)v ohovrajv tori togovtov TrXrjdos 1 ' to yap 

681 a dpotov ovtws dv r) <f)vcns €17] aTrohehioKvla rots 

elpr^pevois fioptoLS. 

Alotl pev ovv TrepLrra Kal Tooavra tov dpidpidv 
tyei 6 lyivos tol cpd, etprjTaL' hioTi 8' ol fiev TrdpLirav 
fjiLKpd ol Se pceydXa, aiTiov to deppLOTepovs etvat 
tt)v (j>voiv tovtovs' tt€TT€lv yap to 9epp,dv SuVaiat 

5 T7]V TpO<f>r)V pL&XXoV, SlOTTCp 7T€p L TT (X) paTO$ 7r\r)p€l$ 

ol dfipojToi paXXov. Kal TrapaaKevd^ei KivrjTiKW- 
Tepovg r) Trjg cftvaeajs OeppoTrjg, a)OT€ vepceoOaL /cat 
fir) peveiv iSpaiovs. a-qpieZov Se tovtov to k'xeiv 
tovs tolovtovs del ti oh twv aKavdcov OJS KIVOV- 
pcevovs TTVKvd' xp& vrai yap rroul Tats aKavOais. 
10 Ta Se Tiqdva piKpov tcdv (j>VTO)v hia^epei tt)v 
cfrvcriv, 6pL<DS he ^wTiKWTepa to>v o-noyyojv ovtol 
yap rrdpLTrav k'xovoi (j)VTOV hvvapuv. r) yap <f>vvis 
pLeTafialvei ovvex&s dird to>v difjvxojv els ra £a)a 

Sid TO)V ^0)VTO)V pi€V OVK OVTWV §6 ^tpCUV, ovtojs 

wgt€ hoKelv TrdpLTrav piKpov 8ia<f>€peiv OaTepov 
15 OaTepov Tto avveyyvs aAA^Aots 1 . 6 piev ovv oiroyyos, 
1 hinc manus recentior E (=E). 

° This is true : but motion is effected mainly by the tube- 
feet, not noticed by Aristotle (vide Ogle). 
b The " sea-squirts." 



because growth has its origin from the stomach. 
Now if there were only one stomach, either the ova 
would be too far away from it, or the stomach would 
entirely fill up the cavity, which would make it 
difficult for the Sea-urchin to move about and to find 
sufficient food to replenish itself. But, as it is, there 
are five ova separated by five intervals, and so there 
must be five departments of the stomach, one for 
each interval. For the same reason there are five 
teeth, since this enables Nature to assign one tooth 
alike to each ovum and each department of the 

I have now stated why the Sea-urchin has an odd 
number of ova, and why it has five of them. Now 
some Sea-urchins have quite small ones, and some 
large : the reason for this is that the latter have a 
hotter constitution, and the heat enables them to 
concoct their food better. This explains why the 
uneatable ones tend to be full of residue. This 
natural heat also induces the creatures to move about, 
and so instead of remaining settled in one place they 
keep on the move as they feed. An indication of 
this is that Sea-urchins of this sort always have some- 
thing sticking on to their spines (which they use 
as feet), a which suggests that they are continually 
moving about. 

The Ascidians & differ very little in their nature from 
plants, but they are more akin to animals than the 
Sponges are, which are completely plants. Nature 
passes in a continuous gradation from lifeless things 
to animals, and on the way there are living things 
which are not actually animals, with the result that one 
class is so close to the next that the difference seems 
infinitesimal. Now a sponge, as I said just now, is in 



681 a 

cooirep eiprjTCLL, Kal ra> ^rjv 7rpoo7T€<f)VKQJS fiovov, 

OLTToXvOelg $€ fjL7} l^V, 6 {10 LCDS TO IS (f)VTOLS 

TravTeXcos' ra Se KaXovfieva oXodovpia Kal ol Trvev- 
fioves, en $e Kal erepa roiavr* iv rrj daXdrrj) 

fjUKpOV Biacf}€p€L TOVTWV TW OLTToXeXvoQcU' CU<j6rjOLV 

20 jJiev yap ovhepiiav e^et, ^rj 8' coGTrep ovra <j>vra 
diroXeXvpiiva. eon he. Kal iv tols imyetots <j>VTOL$ 
kvLa roiavra, a Kal £77 Kal ylverat ra fiev iv iripois 
<f)VTOis, ra oe Kal drroXeXvfJL€va } olov Kal to €k tov 
Ylapvaaoov KaXovpievov vtto tlvojv eTtuneTpov tovto 
yap £77 rroXvv -)(p6vov icpepidfievov dvco irrl rtbv 

25 7TarrdXwv. eon §' ore Kal rd TTjOva, Kal et tl 
tolovtov k'repov yevos y tw fxev irpooTTecjyvKos tfqv 
[jlovov <f>VTW TrapaTrXrjGiov, ra> §* ex €lv tl oapKcijoes 
$6£eL€v dv e-)(€iv riv ataQr\oiv' dSrjXov Se tovto 
TTOTepojs Qeriov. 

"E^et Se tovto to l^wov 8vo TTopovs Kal \ilav 

30 Siaipeutv, fj T€ Six €raL r V v vypoTrjTa ttjv els 
Tpo^rjV, Kal fj rrdXtv 8ta7re/X7ret ttjv v7ToXeLirop.evriv 
iV/xaSa* 7repLTT(x>ixa yap ovSev ioTi SfjXov <r\w, 
<jQOT7€p rdXXa ra oaTpaKohepfxa. Sto pLaXiora Kal 
tovto, Kav el' tl dXXo tolovtov twv ^cdqjv, (f)VTLKOV 
hiKaiov KaXeiv ovSe yap rcbv <f>vTO)v ovSev e^et 

35 TTepiTTOjpLa. Sia fieaov Se XeirTov Sta£a>/xa, iv a> 
to Kvpiov vTrdpy^eiv evXoyov Trjs £a>ijs. as Se 
KaXovoiv ol fiev Kvtoas ol §' aKaXifyas , eoTi fiev ovk 
681 b ocTTpaKoSeppia, aAA' e£a) irLiTTei tqjv 8 Lyprj fiev ojv 
yevcbvy iTrapL^OTepl^ei Se tovto Kal <j>VTW Kal £ojo> 

° Or " sea-cucumbers." 

& The precise reference of this term is not known. 

c Sea-anemones, called by the Greeks " sea-nettles.'* 



all respects like a plant : it lives only while it is 
growing on to something, and when it is pulled off it 
dies. What are called Holothuria and the Sea-lungs ° 
and other similar sea-animals differ only slightly 
from the sponges in being unattached. They have 
no power of sensation, but they live just as if they 
were plants unattached to the soil. Even among 
land-plants such instances exist : living and growing 
either on other plants or quite unattached : for 
example, the plant found on Parnassus, sometimes 
called the Epipetron (Rockplant). If you hang this 
up on the pegs 5 it will keep alive for a consider- 
able time. Sometimes it is doubtful whether these 
Ascidians and any other such group of creatures 
ought to be classed as plants or as animals : In so far 
as they live only by growing on to some other object 
they approach the status of a plant ; but yet they 
have some fleshy substance and therefore probably 
are capable of sensation of a kind. 

This particular creature (the Ascidian) has two 
orifices and one septum ; by one orifice it takes in fluid 
matter for food, by the other it discharges the surplus 
moisture ; so far as can be seen it has no residue like 
the other Testacea. And as no plant ever has any 
residue this is a strong justification for classing it 
(and any other such animal) as a plant. Through its 
middle there runs a thin partition, and it is reason- 
able to suppose that the governing and vital part of 
the creature is situated here. As for what are called 
Knides or Acalephae, c they are not Testacea, it is 
true, but fall outside the defined groups. In their 
nature they incline towards the plants on one side 

Those common to the Mediterranean are more virulent in 
their stinging powers than those of the north. 


rrjv <f>vaiv. rw fJLev yap airoXveaOai Kai irpoo- 


5 Kal to) aladdveaOai rcov ttpogttltttovtcov* €TL oe rfj 
rod gwucltos rpaxvrr]TL xP^ Tai TTpos Trjv GOJTrjpLav 
rw §' dreXes eivcu Kal irpoG^veoOai ra^eaj? rats' 
Trerpais rep ylvei twv <j>vra)v 7Tapa7r\rjoLOV s Kai rw 
TTepLTrajfia firjSev ^x £lv <t>o>v€p6v, arofia S' ^X eiv ' 
SfJLOLov Se rovrw Kal to rwv darepcov iarl ylvos — 
10 Kal yap rovro ttpogttltttov e/c^u/it^et 7roAAd tojv 
doTpicov — rots' t' drroXeXv fie vols twv eLprjfievcov 
£(La>v s otov tols re (laXaKLOLS Kal tols fiaXaKO- 
arpaKois. 6 S' avros Xoyos Kal Trepl twv oorpaKo- 


Td fiev ovv fiopia rd irepl ttjv rpocf)rjv s anep 
dvayKaiov iraaiv vrrapx^tv, e^et tov TTpoeiprjfievov 

15 TpoTrov, Set Be orjXovori Kal twv rots ivatfioLs 
VTTapxpvrwv Kara to Kvpiov twv alodrjoecov e^ett' 
dvdXoyov tl [xopLov tovto yap Set iraaiv vrrapx^w 
tols £ojois. k'ori he roOro rots' fiev fxaXaKLOts iv 
vfidvL K€Lfievov vypov, St' ovirep 6 GTOfiaxos rirarai 
Trpos rrjv KoiXlav, TrpoGTricjyvKe Se rrpos rd TTpavrj 

20 fxaXXov, Kal K-aAetrat fivns vtto tlvwv. tolovtov S' 
erepov Kal tols fxaXaKoorpaKOLS iarl, Kal /caAetrat 
KaKeTvo fjLVTLs • €gtl S* vypov Kal GWfiaTwSes oifia 

TOVTO TO pLOpLOV, T€LV€L Se St' ai)TOV s Ka9aTT€p 

eLprjTaLy Std fxeuov fiev 6 GTOfiaxos* el ydp rjv 
fiera^v tovtov Kal rod TTpavovs, ovk dv rjovvaTO 
25 Xafij3dv€Lv ofiOLCos StdoTaotv €lglovgt}s rrjs Tpo<f>rjs 
Std rrjv tov vwrov GKXrjpoTrjTa . €77t Se Trjs /jlvtlSos 
to evTepov etjwOev, Kal 6 9oX6s TTpos raj ivTepw, 


° That is, dorsal. 


and the animals on the other. Towards the animals, 
because some of them detach themselves and fasten 
upon their food, and are sensible of objects that come 
up against them ; and also because they make use 
of the roughness of their body for self-preservation. 
Towards the plants, because they are incomplete, 
and quickly attach themselves to rocks ; and further, 
because they have no residue that can be seen, 
though they have a mouth. The group of Starfish 
resembles these creatures ; Starfish too fasten on to 
their food, and by doing this to oysters suck large 
numbers of them dry. But Starfish also resemble 
those unattached creatures of which we spoke, the 
Cephalopods and the Crustacea. The same may be 
said of the Testacea. 

The parts connected with nutrition are such as I 
have now described. These must of necessity be 
present in all animals. But there is yet another part 
which every animal must have. These creatures must 
have some part which is analogous to the parts 
which in blooded animals are connected Avith the 
control of sensation. In the Cephalopods this con- 
sists of a fluid contained in a membrane, through 
which the gullet extends towards the stomach. It is 
attached to the body rather towards the upper a side. 
Some call it the mytis. An organ just like this, also 
called the mytis, is present in the Crustacea. This 
part is fluid and corporeal at the same time. The 
gullet, as I said, extends through the middle of it. 
If the gullet had been placed between the mytis and 
the dorsal side, the gullet would not have been able 
to distend sufficiently when the food enters, owing to 
the hardness of the back. The intestine is placed up 
against the outer surface of the mytis, and the ink-bag 



681 b v ^ s y y 

ottojs ore TrXelaTov oLTrexf) Trjs elaoSov /ecu to 
Swipes arroOev fj rod ^Xtiovos Kal Trjs dpx^s. 
or i S' iarl to dvdXoyov rfj Kapolq. rovro to pcopLov, 

80 S^Aoi 6 TO7T0S {OVTOS JCLp loTlV 6 GLVTOs) KCU Tj 

yXvKVTrjs rrjs vyporrjros ws ovaa 7T€7T€pipL€vrj Kal 
aLfJLaTcoSrjg . 

'Ey Se tols ooTpaKohippiois €X €l l x * v T ° v avrov 
tottov 1 to Kvpiov Trjs ala6r)G€a>s y TjTTOV S' iTTiSrjXov. 

7tXt]V $€l ^TjTClV OL€L 7T€pl \X€UOTT\T(X TCLVTTJV TTjV 

dpxrjvy oua ixiv pidvLpLa, tov Se^o/xeVov pcoptov Tr)v 
35 Tpo<f)rjv y Kal Si* ov TTOieiTai Tr)v diroKpiaiv 77 
TTjV a7T€pfJiaTiK7jv rj tyjv rrepLTTco^LaTLKrjV y 60a §€ 

682 a Kal -TTOpeVTlKOL TtDV L^COCOV, OL€i eV TO) fJL€0~LO TWV 

Bg^lcov Kal tcov dptarepcov. 

Tots 8' ivTOfJiois to fiev Trjs TotavTTjs dpx^js 

pLOpiOV, <JL)GlT€p iv TOLS TTpOJTOLS IXlx® 7 } X6yOlS> 
fjL€Ta£i) K€<f)aXrjs Kal TOV 7T€pl T7]V KoiXlav cotI 

5 Se TrXeiojy KaQairep tols lovXcnSeat Kal fiaKpols' 
Slottgp hiaTtpLv6pL€va £77. fiovXtTai piiv yap r) <j>vuLS 
iv rrdoi ptovov ev ttol€lv to tolovtov, Kal ovvapiivr) 
fiev 7T0t€L pcovov eV, ov hvvapiivrj Se TrXela)? SrjXov 

S' iv €T€pOlS €T€pU)V pi&XXoV . 

Td Se TTpos TTjv Tpo<f)7)v pcopta ov naaLv 6pLola)s y 
10 dAAa $Lacf>opdv e^ei ttoXX^v. ivTos ydp tov gto- 
ptaTOS ivloLs piiv iaTi to KaXovj-ievov KevTpov, 
(vcnrepavel ovvdeTov Kal £x ov yXcuTTrjs Kal ^etXcov 

1 tottov Rackham : rponov vulg. 2 ev P : om. vuig. 

3 sic SUY (Swa/xeva bis S) : /cat hvvayiivqv pew, ev Trotet fiovov 
ov Swajxeivi Se -ttXclo) Z : ov hvva^iivq 8' erepyetct Trotct /xdvov h>, 
hwd^u Se 77-Aet'aj- vulg. (cf. 667 b 25). 



up against the intestine ; this is to ensure that it and 
its unpleasantness are kept as far as possible from the 
body's entrance and from the sovereign and most 
noble part. The mytis occupies a place which corre- 
sponds exactly with that of the heart in blooded 
creatures : which shows that it is the counterpart of 
it. a Another proof of this is that the fluid in it is 
sweet — that is, it has undergone concoction and is of 
the nature of blood. 

In the Testacea the part which rules sensation 
occupies the same place but is not so easy to pick out. 
But this source of control should always be looked for 
around some middle position in these creatures : in 
stationary ones, in the midst between the part which 
receives the food and the part where the seed or the 
residue is emitted ; and in those which move about, 
always midway between the right side and the left. 

In insects the part where this control is placed, as 
was said in the first treatise, 6 is situated between the 
head and the cavity where the stomach is. In the 
majority there is one such part, but in creatures like 
the Centipede, that is, which are long in the body, 
there are more than one : so if the creatures are cut 
up they go on living. Now Nature's desire is to make 
this part a unity in all creatures, and when she can, 
she makes it a unity, when she cannot, a plurality. 
This is clearer in some cases than in others. 

The parts connected with nutrition are by no means 
alike in all insects ; indeed they exhibit great 
differences. For instance : Some have what is 
known as a sting inside the mouth — a sort of com- 
bination of tongue and lips, — which possesses the 

° The heart of invertebrates escaped the notice of Aristotle. 
» At Hist. An. 531 b 34. c Cf. 667 b 22 ff. 



682 a 

a/xa Svvapuv rois Se firj k'xovoiv epLirpoodev to 
Kevrpov eoriv ivros rcov oSovrcov roiovrov aiodrj- 

TTjpiOV. TOVTOV 8' €x6fJL€VOV TTaGlV k'vrepOV €vdv KCLl 

15 dirXovv piixP 1 T V$ i£6Sov rod rrepirrcofiaros' ivlois 
Se rovro iXiK7]v e^ei. Ta Se KoiXlav pier a to oropia, 
a 776 Se rrjs KoiXlas to evrepov elXiypevov y ottcos 


*XU irXelovos rpo(j)rjg. to Se rcov rerriycov yevos 
ISlav k'xei pidXiara rovrcov cf>vaiv to yap avro 

20 jJLOpiOV €^€f. GTOpLa Kdl yXwTTCLV OVpLTte^VKOS , Si 

ov KaOarrepel Sid pittfs Sex^ai T W Tpocfirjv aird 
rcov vypcov. rrdvra fikv ovv iorlv SXiyorpocpa ra 
evrofia rcov i^cocov, oi>x ovrco Sid piKporrfra cos 
Sid ifjvxpdrrjra (to yap 6epf.tov Kal Seirai rpocfrijs 

Kal TT€TT€l TTjV rpO(f>7]V Ta^COJ?, TO Se IpVXpoV a- 

25 rpO(j)ov) i fidXiura Se to rcov rerriycov yevos ' iKavrj 
yap rpocfyrj rep acopari rj 4k rod Trvevpiaros vtto- 
jievovoa vyporrjs, KaOdnep rois i(f>rjpepois ^cpois 
(ylverai Se ravra rrepl rov II 6vrov) y ttXtjv eKeiva 
piev ^fj fjLias rjpepas xP° vov > Tavra Se irXeiovcov 
fiev rjfieptov, oXlycov Se rovrcov* 

30 'E^ei Se Trepl rcov ivros vrrapxdvrcov poplcov rois 
^cpois eipryraiy irdXiv rrepl rcov Xoirrcov rcov eKrds 
iiravireov. dpKreov 8' and rcov vvv eiprjpevcov, 
aAA' ovk aft Sv aireXliropieVy ottcos dird rovrcov 
Siarpifirjv eXdrrco ixdvrcov irrl rcov reXeicov Kal 
evaij-Lcov £>4 )C ° 1 ' ° Xoyos axoXd^rj fiaXXov. 

35 VI. Ta jiev ovv evropia rcov ^epeov ov TroXvpeprj 
fxev rov dpiOpov iariv, opcos 8' k'xei irpds a'AA^Aa 


character of both. Those that have no sting in front 
have a sense-organ of that sort behind the teeth. 
After the mouth, in all insects comes the intestine, 
which is straight and simple right up to the residual 
vent. (Sometimes, however, it has a spiral in it.) 
And some there are which have the stomach next 
after the mouth, while from the stomach runs a 
twisted intestine ; this gives the bigger and more 
gluttonous insects room for a larger amount of food. 
Of all these creatures the grasshoppers are the most 
peculiar. In them the mouth and tongue are united 
so as to make one single part, and through this they 
draw up their nourishment from fluid substances as 
through a root. All insects take but little nourish- 
ment ; and this is not so much because they are 
small as because they are cold. (Heat needs nourish- 
ment and quickly concocts it ; cold needs none.) 
This is most marked in the grasshoppers. They find 
sufficient nourishment in the moisture which the air 
deposits ; so do the one-day creatures which occur 
around the Black Sea. Still, they live only for the 
space of a day ; whereas the grasshoppers live for 
several, though not many, days. 

Now that we have spoken of the internal parts of 
animals, we must go back and deal with the remainder 
of the external parts. We had better begin with the 
creatures of which we have just been speaking, and 
not go back to the point where we left the external 
parts. This will mean that we take first those which 
need less discussion, and that will give more time for 
speaking of the " perfect " animals, i.e. the blooded 

VI. Insects first, then. Though their parts are not External 
numerous, insects differ from one another. They all PA 


S:aoooac. -oAi'roOc t:ex yao ecTi "cit-j Sta to 

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1 r-i— - Peck: t::tc V: ~zC~' r nzl J. : rz-Jrzs Or.r. 

1 iz„-^_ O^Ie: f;cx-- " * ^rrs-j Piatt, 



have numerous feet ; this is in order to make their (<*>) insects, 
motion quicker, and to counteract their natural slow- 
ness and coldness. Those which are most subject to 
coldness owing to their length {e.g. the Centipedes) 
have the greatest number of feet. Furthermore, 
these creatures have several sources of control ; and 
on that account they have the " insections " in their 
bodies, and the numerous feet which are placed in 
precise correspondence. 

Those that have fewer feet are winged by way of 
compensation. Some of these flying insects live a 
wandering life and have to go abroad in search of 
food ; so they have a light body and four wings, two 
on either side ; such are the bees and the kindred 
tribes. The small ones have only two wings all told 
— like the flies. Those that are heavy and sedentary 
in their habits have the larger number of wings like 
the bees, but they have shards round their wings 
{e.g. the Melolonthae a and similar insects) to preserve 
them in their proper condition ; for, as these creatures 
are sedentary, their wings arc more liable to be 
destroyed than those of the nimbler insects ; and 
that is why there is this protection round them. 
An insect's wing is not divided, and it has no shaft. 
In fact, it is not a wing at all, but a membrane of skin, 
which being dry detaches itself of necessity from the 
creature's body as the fleshy part cools off*. 

I have already stated some reasons why these 
creatures have " insected " bodies : there is another, 
viz. it is so that they may curl up and thus escape 
injury and remain safe. It is the long ones that roll 
themselves up, and this would be impossible for them 
if they were not insected. Those that do not roll up 
° Perhaps cockchafers (Ogle). 



682 b 

eXiKTa avrwv oKXrjpvverai fiaXXov avviovra €tV ras 
25 TO{id$. SrjXov oe rovro ycverai diyyavovrwv > olov 
€7tl rwv KaXovyievwv Kavddpwv (f>oprjdevra yap 
OLKLvrjTL^ec, koll to owfia ylverai GKXrjpov avrwv. 
avayKCLLOv 8' evrofiotg avrolg etvat' rovro yap iv 
rfj ovoia avrwv virdpyei to TroAAas" k'yjeiv apyds, Kal 
80 ravrr] 7rpooeoiKe rols </)Vtol$. wurrep yap ra <f>vrd, 
Kal ravra oiaipovfieva ovvarai ^rjv, ttXtjv ravra pikv 
/xe^pt rivos, €K€iva 8e Kal riXeta yiverac rrjv <f>voiv 
Kal Svo i£ ivog Kal irXeiw rov dpcOfiov. 

"E^et 8' evta rwv ivropcwv Kal Kevrpa Trpos 
fiorjdeiav twv pXa7rrovrwv . to fiev ovv Kevrpov 

S5 TOtS" \J<€V €fjL7TpOO0€V €0"Tt TOtS* S* 07TLoQeV 3 Tots pL€V 

epLTTpooOev Kara rrjv yXwrrav, rots 8' OTTioOev Kara, 
ro ovpalov. a>a7T€p yap Tots" eXe^aac to rwv 
ocrfiwv ato8r}rr}pLov yeyevrjrat xprjcripiov rrpog re 

683 a TTjv aXKTjV Kal T7]v rrjg rpocf>rjs \pr\oiVy ovrwg TWV 

ivrojiwv ivlois to Kara rrjv yXwrrav reraypLevov 
alaOdvovral re yap rovrw rrjs rpo<j)rjg Kal avaXay,- 
fidvovGi Kal -npoodyovrai avrr\v. oaa Se firf ianv 
avrwv iparpoad 6 Kevrpa, 686vra$ e^€t to, fikv 
5 iSworjs X^P LV T( * ^ T0 ^ Xafifidveiv Kal -npoadyeadai 
tt]v rpocfyrfv, olov ol re€s Kal to twv pLeXir- 
rwv rraawv yivos. oaa 8' omaOoKevrpd ian, 8ta 
to 9v[i6v e^etv ottXov ex €L t ° Kevrpov. eyovai oe 
ra [lev iv lavrols ra Kevrpa, KaOdrrep at fjceXirrai 
Kal ol a<f>rjt<es, 8ta to TTrrjvd elvai' Xenrd [lev yap 
io ovra Kal e£w ev(j)6apra {aV) 1 rjv el Se rrayea tfv 2 

WOTTCp TOLS GK0p7Tl0lS, fidpOS S.V ITapeX^eV , TOtS* 8<E 

1 (av) Ogle. 2 Se iraxza Piatt : S' airelxev vulg. 



increase their hardness by closing up the insections. 
This is obvious if you touch them — e.g. the insects 
called Canthari (dung-beetles) are frightened when 
touched and become motionless, and their bodies 
become hard. But also it is necessary for them to 
be insected, for it is of their essential being to have 
numerous sources of control ; and herein they re- 
semble plants. Plants can live when they are cut 
up ; so can insects. There is a difference, however, 
for whereas the period of survival of a divided insect 
is limited, a plant can attain the perfection of its 
nature when divided, and so two plants or more come 
out of one. 

Some of the insects have a sting as well, for defence 
against attackers. In some the sting is in front, by 
the tongue ; in others it is behind at the tail-end. 
Consider the elephant's trunk : this is its organ of 
smell ; but the elephant uses it as a means of exert- 
ing force as well as for the purposes of nutrition. 
Compare with this the sting of insects : when, as in 
some of them, it is ranged alongside the tongue, not 
only do they get their sensation of the food by means 
of it, but they also pick up the food with it and convey 
it to the mouth. Those which have no sting in front 
have teeth ; which some of them use for eating, 
others for picking up the food and conveying it to the 
mouth, as do the ants and the whole tribe of bees. 
Those that have a sting at the back are fierce crea- 
tures and the sting serves them as a weapon. Some- 
times the sting is well inside the body, as in bees and 
wasps. This is because they are winged, and a deli- 
cate sting on the outside of the body would be easily 
destroyed ; on the other hand, a thick one such as 
scorpions have would weigh them down. Scorpions 



683 a 

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elvai TTpOS TTjV dXKTjV. $L7TTepOV 8' OV0€V €OTLV 

omoOoKevrpov Sid to doOevrj yap Kal fJLLKpd elvai 
is hlirrepd eanv LKdva ydp rd puKpd alpeudat vtto 
tojv eXarrovojv rov dpiOpiov. hid ravrd he rovro 
koI efjiTTpooOev eyei to Kevrpov doOevrj ydp ovra 
fioXis hvvarai rots omoOev 3 rv-rrreiv. rd Se 
TroXvTTTepa, Sid to fiet^co ttjv $vciv elvai, irXeidvcov 

T€TV)(T)K€ TTTepOJV Kal layVZl TOiS OTTLodeV fJLOpiOiS. 

20 fieXnov 8' ivb^xofJievov jirj ravro dpyavov errl 
dvofj.ola£ k\eiv XPV aeL ^» dXXd to jiev dfjLWTiKov 
d^vrarov, to Se yAa>TTi/<:ov ao[JL<f>6v Kal OTraoTiKov 
rfjs rpo(f>rjs. ottov yap evSex €TaL xPV°^ ai ^ va ^ v 
€7tI SiT epya Kal [at) ejinohL^eiv Trpds erepov, 
ovSev rj <f)vois €ia)0e Troielv tooTrep rj x a ^ KeVTlK V 

25 upds evreXeiav d/feAio-KoAtn^ioy* dAA' ottov (jlt) 
eVSe^eTat, Karaxprjrai rep avrcp ivrl TrXeloj k'pya. 

Tovs 8e TTodas rovs TTpoaOlovs fJiel^ovs evia tou- 
rcov e^etj ottojs eTreiSr] Sid to a/cA^pd^^aA/xa elvai 

OVK aKpifirj TTjV OljsLV k'xOVOi, rd TTpOOTTiTTTOVTa rots 

irpooOiois aTTOKaOaLpayoi OKeXeoiv o-nep Kal tbai- 
80 vovrai -noiovoai at re fjivtai Kal rd fJLeXirrd)Srj rcov 
£a)a)V del yap x a P aK ^ OV(Jl TTpooOlois OKeXeoiv. 
rd 8' oTTLGOia [Aetata rcov \iiotov Sid re rrjv fidoicnv 
Kal TTpos to atpeodai paov dird rrjs yrjs dva-ner- 

1 KtpKov Z (coniecerat Ogle) : xevrpov vulg. 
2 T&VT7) Ogle : tolvt vulg. 
3 OTnodev Ogle, Thurot : efinpoaOev vulg. 

° The principle of "division of labour " in a living organism, 
not stated again until 1827 (by Milne Edwards). See Ogle's 



themselves, being land-creatures and having a tail, 
are bound to have their sting on their tail ; otherwise 
it would be no use for exerting force. No two- 
winged insect has a sting at the rear ; these are small 
weak creatures, and can be supported by a smaller 
number of wings : that is why they have only two. 
The same reason explains why they have their sting 
in the front : owing to their weakness they cannot 
well deliver a blow with their hind parts. Many- 
winged creatures, on the other hand, owe their 
greater number of wings to their own greater size, 
and so too their hind parts are stronger and bear the 
sting. It is better, when it is possible, that one and the 
same organ should not be put to dissimilar uses ; that 
is. there should be an organ of defence which is very 
sharp, and another organ to act as a tongue, which 
should be spongy and able to draw up nourishment. 
And thus, whenever it is possible to employ two 
organs for two pieces of work without their getting in 
each other's way, Nature provides and employs two. a 
Her habits are not those of the coppersmith who for 
cheapness' sake makes you a spit-and-lampstand 
combination. Still, where two are impossible, Nature 
employs the same organ to perform several pieces 
of work. 

Some insects, whose eyesight is not distinct owing 
to their eyes being made of some hard substance, have 
specially long forefeet, which enable them to clear 
away anything that comes down on to the eyes. 
Flies and bees and the like are obvious examples : 
they are always crossing their front legs. These 
creatures' hind legs are longer than their middle ones 
for two reasons : (1) to assist them in walking, and 
(2) to lift them more easily off the ground when they 

si 34/7 


683 a 

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<j>avep6v s otov at r' aKpioes Kal to twv ifjvXXcbv 
35 yevos' orav yap Kapi^avT eKTelvj] ttoXiv, avayKaiov 
oltto rrjs yfjs r\p9ai, ovk epirpooOev 8* dAA' 
683 b omcrOev povov e^owi to, TrrjSaXitbSrj ai aKpioes' 
rrjv yap KapL7TT)v avayKaiov eiaco KeKXaodai, tcov 
oe TTpooOlojv kcoXcov ovSev cgtl toiovtov. e^aVoSa 
Se tcl roiavra irdvT iarl avv tol$ olXtlkols piopioLS. 
VII. Tcov 8' ouTpaKOoippcov ovk can to owpa 

5 7ToXvpep€£. TOVTOV 8' aiTlOV TO pOVtpOV aVTCVV 

etvai ttjv <j)vaiv noXvpepeoTepa yap avayKaiov 
elvai tcov X^cpcov rd KtvrjTiKa 8td to (jrXelovsy 1 etvai 
avTtov it pa^ets* opydvtov yap Setrai irXeiovcov ra 
7rXei6vcov pere^ovra Kivrjaecov. tovtcov 8e to, pev 
OLKLvqra irdpirav earl, rd oe piKpds peTex^t ki- 
10 vqoetos' dAA' rj <f>vois irpbs acoTTjplav avTOis rrjv 

TCOV OOTpaKLOV OKXrjpOTTJTa 7T€pL€0rjK€V. €OTl $€ 

Ta pev povoOvpa to, he hidvpa avTcov, tcl oe oTpop- 
fitohr], KaOdirep eiprjTat irpoTepov Kal tovtcov Ta 
pev eXiK7]v e^ovTa, otov Kr/pvKes, Ta oe oc^acpoeiorj 
povov t Kaddirep to tcov lyivwv yevos. Kal tcov 
15 hiQvptov Ta pev Igtiv dvaiTTVKTa, otov KTeves Kal 
pves (eirl OaTtpa yap GvyKeKXeioTai, cooTe av- 
oiyeoOai eVt QaTepa Kal ovyKXeUaOai) , Ta 8' eir* 

dpcf>CO CFVp7T€<f)VK€V, otoV TO TCOV GCoXrjVLOV y€VO$. 

aVavTa 8e tcl oaTpaKooeppa, KaOdnep ra tf>VTa> 
20 KOTTCO TTJV K€tf)aXr]V e^et. tovtov 8' diTiov OTl 
KaTcoOev Xapfidvei ttjv Tpocfrrfv, cocnrep ra cj>VTa 
tols pleats > ovpfiaivei ovv avTols ra pev KaTco 
avco exew, Ta o avco KaTto . ev vpevi o eoTi, ot 
1 <*rAeiW> Peck: (iroXXas) Piatt. 



rise in flight. This peculiarity is even more notice- 
able in the leaping insects, such as locusts and the 
various sorts of fleas, which first bend their hind legs 
and then stretch them out again, and this forces them 
to rise up from the ground. The rudder-shaped legs 
which locusts have are at the rear only and not in 
front ; this is because the joint must bend inwards," 
and no front limb satisfies this condition. All 
these creatures have six feet, inclusive of the parts 
used for leaping. 

VII. In Testacea the body is not divided into (5) Testacea, 
several parts, owing to their being of stationary 
habits, as opposed to creatures which move about : 
the latter are bound to have more parts to their body 
because their activities are more numerous, and the 
more motions of which a species is capable, the more 
organs it requires. Now some of the Testacea are 
altogether stationary : others move about but little ; 
and so, to keep them safe, Nature has compassed 
them about with hard shells. Some of them are (as I 
said earlier b ) one-valved, some two-valved ; and some 
conical, either spiral like the Whelks, or spherical 
like the Sea-urchins. The two-valved shells are 
divided into (a) those which open — i.e. which have a 
joint on one side and can open and shut on the other ; 
e.g. the scallops and mussels ; (b) those which are 
joined together on both sides, e.g. the group of razor- 
fishes. In all Testacea, just as in plants, the head is 
down below. The reason for this is that they take up 
their food from below, as plants take it up by their 
roots ; so they have their nether parts above and their 
upper parts below. These creatures are enveloped 
in a membrane, and through this they strain fresh- 

• See note on 693 b 3, p. 433. * At 679 b 16. 



ov htrjOet to ttoti\lov Kal Xafifidvei ttjv rpo(j>r}V. 
€^et he Ke<f>aXf)V fiev ixavTa, ra he rod adjfiaros 
fjiopia Trapa to rfjs Tpofirjs heKTiKov dvwvvfia 

25 VIII. Ta Se puaXaKoarpaKa zrdvTa Kal rropevriKdy 
hid rrohcov k'xei TrXrjOos. eon he yevrj fiev rerrapa 
ra fieyicrr avTcov ol re KaXovfxevoi Kapafioi Kal 
doTdKoi Kal Kapihes Kal KapKivoi' tovtojv 8' 
eKacrrov 7rXela> eihrj earl hia<f>epovra ov fxovov Kara 

30 rrjv fiop(f>r)v dXXd Kal Kara to fieyedos rroXv' rd 
[lev yap fieydXa ra he pAKpa TrdpiTTav avra>v eoriv. 
t<x {lev ovv KapKivwhr] Kal Kapafiwhr) rrapopLoi* 
earl tco ^TjAa? e%eiv df,L(f)6Tepa, Tavras 8' ov 
TTOpeLas e)(ovoi xdpiv, dXXd rrpos to Xafieiv Kal 
KaTaoyeiv dvrl ^eipayv. hio Kal Kafiirrovoiv evav- 

35 tLojs ravras rols ttoo'iv tovs p.ev yap eirl to kolXov 
Tag 8' errl to nepi^epes Kafimovai Kal eXlaoovoiv 
ovtoj yap xpr]oip,ai TTpos to Xafiovoai rrpoocfiepeodai 

684 a T7JV TpO(f)rjV. 

Aiacfrepovcri 8' fj ol puev Kapafioi e^ovaiv ovpdv, 
ol he KapKivoi ovk e'xovaiv ovpdv toIs fiev yap hid 
to vevGTiKois elvai ^p^crt/xos rj ovpd (veovoi yap 
aTTepeihofievoi oiov TrXdrais avrais), rolg he Kap- 
5 kivois ovhev xprjoifjiov 8td to rrpoayeiov elvai tov 
fiiov 1 avTcbv Kal elvai rpojyXohvTas . oooi 8' avTo>v 
ireXdyioi eloi, hid tovto ttoXv dpyorepovs e^pvai 
rovs irohas 2 TTpos tt)v Tropelav j oiov at re fiaiai 
Kal ol 'HpaKXewriKol KaXovpievoi KapKivoi, on 
oXLyrf Kivrjaei xpGyvrai, aAA' r) aa)Tt]pia avrois 
io ra> doTpeiwheis elvai yiveTav hid ai fiev jialai 

1 to jStov Bekker per typothetae errorem. 
2 avTtov post iro$a$ vulg. : om. Y. 



water to drink, which is their way of taking nourish- 
ment. All of them possess a head, but except for 
the part which takes in the food none of the other 
parts has a special name. 

VIII. All the Crustacea can walk on land as well as (c) Cru^. 
swim; and hence they all have numerous feet. There tacea * 
are four main groups of Crustacea, called (l) Carabi ; 
(2) Astaci; (3) Carides; and (4) Carcini. a Each of 
these contains several species which differ not only 
in shape, but also in size, and that considerably, for 
some species are large, others extremely small. The 
Carcinoid and the Caraboid Crustacea resemble each 
other, in both having claws. These claws are not for 
the sake of locomotion, but serve instead of hands, 
for catching and holding ; and that is why they bend 
in an opposite direction to the feet, which bend and 
twist toward the concave side, while the claws bend 
toward the convex side. This makes the claws 
serviceable for catching hold of the food and convey- 
ing it to the mouth. 

The two groups, Carabi and Carcini, differ in that 
the former have a tail and the latter have not. The 
Carabi find a tail useful because they are swimmers : 
they propel themselves Math it as though with oars. 
A tail would be useless to the Carcini, which spend 
their lives near the land and creep into holes and 
crannies. Those that live out at sea and move about 
but little, and owe their safety to their shelly exterior, 
have for these reasons feet which are considerably less 
effective for locomotion : examples of this are the 

a Roughly, these four divisions may be represented by our 
own groups, thus : (1) lobsters ; (2) crayfish ; (3) prawns and 
shrimps ; (4) crabs. 



A€7TT0OKeAeLS } oi §' 'Hpa/cAeom/cot ixtKpoaKeXets 

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rot? p,iKpol$ IxOvSlois, k'xovoi rovg reXevralovg 
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^X €LV XV^S' ^ ^X ovaL ^ t( * r ° nXeiovs ^X eiV 
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Ta §' iv TOtS" V7TTLOLS fJLOpid K(li 7T€pl TTjV K€~ 

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^Aetat tcuv dppevcov Kapdfitov ex oV(JL > Ka ^ TC * ^ v 
TO) eTTLTTTvyfiaTL BaavTepa at OrjXetat /cap/ctVot 
tcov dppevcov y Scd to eKTeiveiv ra coa rrpos aura, 
dAAd jjcrj diroQev, coairep ot IxBves /cat TaAAa tol 
{ojol) 1 Tt/crovra* evpvxcopeaTepa yap ovra /cat piet^co 
25 x<*>P av ^X €L T °^$ (p ^ f^aXXov. oi fiev ovv /capa,8ot 
/cat ot KapKivoL TrdvTes tt)v Seftdv exovai XV^V V 
pce^co /cat lux^poTepav rot? yap Besots Trdvra 
7re<j)VKe ra ^coa Bpdv pL&XXov, r) Be <f)VULS aTroBlBco' 
oiv del toXs xPV a @ aL Bwapcevois gkclotov r) fiovcos 
rj fiaXAov, olov ^auAtdSovras' /cat oSovras" /cat 
80 KepaTd /cat TrXrjKTpa /cat rrdvTa rd rotaura jiopia, 
00a rrpos f3or)6eiav /cat dA/c^v eoTiv. 2 

Ot S* dcrra/cot pLovot, orroTepav dv tvxcoolv 
exovoi jjcel^co tcov ^tjAcov, /cat at OrjXeiai /cat ot 

1 <a>d) Peck : r^KOvra S : KvtaKOvra PY : (poroKOviTa Ogle. 
2 eorcv Peck : etaiv vulg. 



Maiae a (whose legs are thin) and the crabs called 
Heracleotic (whose legs are short). 

The little tiny crabs, which are found among the 
catch with small fishes, have their hindmost feet flat, 
like fins or oars, to make them useful for swimming. 

The Carides differ from the Carcinoids in having a 
tail j and from the Caraboids just mentioned in not 
having claws. Claws are absent because they have 
more feet : the material for their growth has gone 
into the feet. And they have more feet because they 
swim about more or move about more. 

As for the parts on the under b surface around the 
head, in some animals these are formed like gills so as 
to let in the water and to discharge it ; the lower 
parts, however, of female crabs are flatter in formation 
than those of male ones, and also the appendages on 
the flap are hairier. This is because they deposit 
their eggs there instead of getting rid of them, as the 
fishes and the other oviparous animals do. These 
appendages are wider and larger and so can provide 
more space for the eggs. In all the Carabi and in 
all the Carcini the right claw is bigger and stronger 
than the left. This is because all animals in their 
activities naturally use the right side more ; and 
Nature always assigns an instrument, either ex- 
clusively or in a better form, to those that can use it. 
This holds good for tusks, teeth, horns, spurs and all 
such parts which serve animals for assistance and 

In Lobsters only, whether male or female, it is 
a matter of chance which claw is the bigger. The 

° Probably the spiny spider-crab. 
6 That is, ventral. 



684 a 

dpp€V€$. CLLTtOV Se TOV fX€V €^€tV XV^S ° Ti ^ V T< ? 

35 yevei elol ra> exovri ^Aa?* rovro 8' draKroJs 

684 b €XOV<JlV OTL 7T€7T T)p<jQ VTdl KCLI OV XP WVTai ^ ° 
7T€(f>VKaOLV, dXXd 7TOp€tCLS X^P iV - 


Kal rives Sca(j)opal irpos dXArjXa, rcov r dXXtov Kal 
rlvi Stou^epei rd dppeva row OrjXeLtov, €K re rwv 
5 avaropLwv dewpeiodw Kal e/c rwv laropcwv rwv 
nepl rd £a)a. 

IX. Twv Se naXaKLCDv irepi {lev rwv evrog 
eipiqrai rrporepov, wuirep Kal uepl rwv aXXwv 
t^wwv €Krog S' e^ei ro re rod awpiaros Kvros, 
dSiopiarov ov, Kal rovrov irohas k'piTTpooBev rrepl 
rqv KecfraXrjVt evros fiev rwv 6<f)8aXpLwv t rrepl Se 

10 to arofia Kal rovs ohovrag. rd fxkv ovv dXXa £,tua 
rd e^ovra Trohas rd fiev epL7rpoo0ev e^ei Kal 
omoOev, rd 8' €K rod TrXayloVy woTrep rd TroXvrroha 
Kal avaipa rcov ^totov rovro Se ro yevos Ihlws 
rovrwv irdvr as ydp k'xovGi rovs rrohag inl ro 
KaXovfievov epLirpocrOev. rovrov 8* alriov on 

15 ovvrjKrai avrwv ro omoOev n pos ro ep.7Tpoa9ev, 
wairep rwv ourpaKoheppLwv rols orpopifSwheoiv. 
oXws ydp rd oarpaKoSepfia e^ei rfj jj,ev ojxolws 
rocs pLaXaKOorpaKois > rfj Se rolg paXaKiotg. fj 
[lev ydp e^wdev ro yewSes ivros ok ro capKwSes, 
rots fxaXaKoarpaKOiSy ro Se a^^/xa rod owpLaros 

20 6V rponov ovvecrrrjKe, rols /xaAa/a'ois'j rporrov fiev 

° See Hist. An. 525 a 30—527 b 34, 541 b 19 ff. 
b At 67S b 24 ff. 

c The theory that the cuttle-fish is comparable to a verte- 
brate bent double was put forward in a paper read before the 
Academy of Sciences in 1S30, and was the origin of the famous 

PARTS OF ANIMALS, IV. viii.-ix. 

reason why they have claws is because they belong 
to a group which has claws ; and they have them 
in this irregular way because they themselves are 
deformed and use the claws not for their natural 
purpose but for locomotion. 

For an account of every one of the parts, of 
their position, and of the differences between them, 
including the differences between the male and the 
female, consult the Anatomical treatises and the 
Inquiries upon Animals. a 

IX. With regard to the Cephalopods, their internal (J) Cepha- 
parts have already been described, as have those lo P° ds - 
of the other animals. b The external parts include 

(1) the trunk of the body, which is undefined, and 

(2) in front of this, the head, with the feet round it : 
the feet are not beyond the eyes, but are outside the 
mouth and the teeth. Other footed animals either 
have some of their feet in front and some at the 
back ; or else arranged along the sides — as with the 
bloodless animals that have numerous feet. The 
Cephalopods, however, have an arrangement of 
their own. All their feet are on what may be 
called the front. The reason for this is that their 
back half is drawn up on to the front half, just as 
in the conical-shelled Testacea. And generally, 
though in some respects the Testacea resemble the 
Crustacea, in others they resemble the Cephalopods. 
In having their earthy material outside and their 
fleshy material inside, they resemble the Crustacea ; 
but as regarding the formation and construction of 
their body they resemble the Cephalopods — all of 

controversy between G. St-Hilaire and Cuvier about unity of 
type. This controversy excited Goethe more than the revolu- 
tion of the same year. (Ogle.) 

M 2 355 


684 b 

nva f navr<x ) jidXtara oe tcjv GTpofxpwocov ra 
exovra ttjv iXiK-qv aii(f>OTepojv yap tovtov &x ei 
tov TpQirov 7} <f)V(ji$ x ' et propter hoc ambulant uni- 
formiter {aXX ovf KaOdrrep GVfifiefirjKev errl twv 
rerpaTTohwv t^wwv Kal twv avdpwrrwv, homo vero 
25 habet os in capite, scilicet in parte superiori corporis. 
€TT€Lra tov GTOfxaxov, erreira be ttjv KoiXLav, arro be 
Tavrrfs to evTepov fJ-expt- T V$ bie£6bov tov rrepLT- 


ivalfiocs ^cLoLSi Kal /xerd ttjv Ke<f>aXrjv eoTiv 6 KaXov- 
fi€vo<; 9d)pa£ } Kal rd rrepl tovtov rd be Xolttcl jiopia 
30 tovtcov T€ X®-P LV ^ l ' €Ka T ^S" KivrjGews TTpoaedrjKev 
rj (frvcris, olov to. tc TrpoaBia KwXa Kal rd ottlgQev, 
fiovXeTai be Kal toXs naXaK0GTpa.K0i$ Kal roTs 
evrofJiOLS rj y evBvwpla twv evTOGOibiwv tov avTov 
€X €LV TpOTTOV, Kara oe rds" VTrrjpeGias tcls e£wdev 
KivrjTiKas bia<f>epei twv evaijiwv. rd oe fiaXaKid 
re Kal (ra) 3 GTpoyL^wbir] twv oGTpai<obepfiwv e^6t 

1 sequitur locus corruptus. quae corrigi possunt sec. vers, 
arabicam correxi, suppo^iticia eieci, amissa e versione latina 
Mich. Scot supplevi. text. vulg. habet rj <f>vats woTrep el tis 
vorjaeiev eV evdeias, KaBanep ovfifSefirjKev eVt rwv T€Tpa7r6Bu>v 

t,<LoiV KOL TUiV dvOpWTTWV, TTpUiTOV fl€V €7tI aV/)a> TO) dl'CJ GTOpLaTl 

Tjjs evdeias /caret to A, erreiTa <«:ara addunt PY> to B tov 
arofiaxov, [to Be om. PY] T ttjv KOiXtav oltto Be tov evrepov 
/zexpi tt}s Bte£6Bov tou TreptTTtu/xaTO?, g to A. tovtov p.ev ovv 
tov Tponov e^et toI? eiai/iots" £wois, Kal irepi tovto eariv r\ 
K€<f>aXT] Kal 6 8a)pa£ KaAovp:evo$ (koX. $u>pa£ SU)* tol Be Xoiira, 
etc. vide et quae p. 432 scripsi. 

2 <&U' ov> Peck. 3 <to> Peck. 



them do so to some extent, but most markedly 
those conical Testacea which have a spiral shell, 
since both these classes have this natural struc- 
ture ° ; and therefore they walk with an even gait, 
and not as is the case with quadrupeds and man. 6 
Now man has his mouth placed in his head, vis. in the 
upper part of the body, and after that the gullet, then 
the stomach, and after that the intestine which 
reaches as far as the vent where the residue is dis- 
charged. This is the arrangement in the blooded 
animals, i.e., after the head comes what is known as 
the trunk, and the parts adjoining. The remaining 
parts (e.g. the limbs at front and back) have been 
added by Nature for the sake of those which I have 
just mentioned and also to make movement possible. 
Now in the Crustacea too and in the Insects the 
internal parts tend to be in a straight alignment of 
this kind ; though with regard to the external parts 
which subserve locomotion their arrangement differs 
from that of the blooded animals. The Cephalopods 
and the conical-shelled Testacea have the same 

° The passage which follows has been badly corrupted by 
references to a diagram which have ousted the text. The 
words in italics have been translated from the Arabic version, 
of which Michael Scot's Latin translation is given opposite, in 
default of the original Greek. See supplementary note on 
p. 432. 

b This refers to their uneven progression by moving first 
one side of the body and then the other. The Testacea, how- 
ever, " have no right and left" (De incessu an. 714 b 9), and 
their movement was evidently an awkward problem for 
Aristotle. He reserves them until the very end of the De 
incessu, and he has to admit that they move, although they 
ought not to do so ! They move -napa <£uW. The mechan- 
ism of their motion can be detected by the microscope, and is 
known as ciliary. See also De incessu, 706 a 13, 33, Hist, 
An. 528 b 9. 



685 a avTols pcev TrapaTrXrjOLCos > tovtols 8' dvreGTpafi- 

fJL€VO)S' K€KGL£JL7TTCLl yap T) TcXeVTTJ 77/30? TTjV apxrfv, 

wo7T€p av el tls rrjv evQeiav [eft rjs to E] 1 Kapuipas 
irpoaaydyoi to A irpos to A. ovtojs yap KeLpbdvcov 
vvv twv evroaOlcov irepiKeirai tols ptev piaXaKLOLS to 
kvtos, o KaXelrai piovov iirl rcov ttoXv7t6Scov KecfyaXirp 
tols 8' oarpaKohlpjiois to tolovtov Iotlv 6 OTpopL- 
j8o?. OLa<f>£p€L 8' ov&ev dXXo irXfjv otl tols pier 
[XOlXolkov to irepii;, tols Se GKXrjpov Trepl to aapKcoSes 
TrepiidrjKev rj (f>voLS, ottccs oco^tcll Sta ttjv ?>voklvv\- 
oiav Kal Sta tovto to TrepLTTOjpia tols t€ plolXolkCols 
to i£4px€TCLL irepl to orTOfia Kal tols crTpopficbSecri, 
ttXtjv tols /xev ptaXaKLOLs KaTwdei', toTs Se GTpopL- 
ficbSecTLV €K tov irXaylov . 

Aia TOLVTTjv pcev ovv T7)v OLTLav tols pcaXaKLOLS ol 


rj tols dXXoLs. exovaL 8' avopLOLCOs al o-qnlaL Kal 
t5 al t€v6lo€s tols ttoXvttool Sta TO VeVGTLKal piovov 

€LVaL, TOVS 0€ Kal TTOp€VTLKOVS* Ctt pi€V yap TOVS 

dva)6ev tu>v ooovtcov (el; pLLKpovs} 2 ex ovai > koI 
tovtojv tovs iaxaTovs ovo pLel^ovs, tovs 8e Xolttovs 


yap tols TtTpaiTOGL tol orriadLa lax v P OT€ P a KcbXa, 
Kal TavTaLs p.£yLOT0L ol koltojOcv {wooes)*' to yap 
20 cf>opTLOv ovtol e^ouat Kal klvovol /xaAtora. Kal ol 
eaxaTOL 8vo puel^ovs tcov [idaajv, otl tovtols ovv- 

1 seclusi ; post tJ? add. Z to oXov faai vid. p. 432. 

2 Schneider ex Gazae vers, (senos exiguos) ; sex S ; piKpovs 
Z (sed -nohwv pro oSovrtov), idem E teste Buss. 

3 Trdurcov Ogle : tovtcov vulg. 4 <77oSe?> Rackham. 


arrangement as one another, but it differs completely 
from that of the others, as the tail-end of these 
creatures is bent right over to meet the front, 
just as if I were to bend the straight line over 
until the point D met the point A. Such 

A B C D 

then, is the disposition of their internal parts. 
Round them, in Cephalopods, is situated the sac (in 
the Octopuses and in them only it is called the head) : 
in the Testacea the corresponding thing is the conical 
shell. The only difference is that in the one case 
the surrounding substance is soft, and in the other 
Nature has surrounded the flesh with something 
hard, to give them the preservation they need owing 
to their bad locomotion. As a result of the above- 
mentioned arrangement, in both sets the residue 
leaves at a point near the mouth : in the Cephalopods 
under the mouth, in the conical Testacea at the side 
of it. 

So what we have said explains why the feet of 
Cephalopods are where they are, quite differently 
placed from all other animals' feet. Sepias and 
Calamaries, however, being swimmers merely, differ 
from the Octopuses, which are walkers as well ; they 
have six small feet above the teeth, and of these the 
ones at each end are larger ; the remaining two out 
of the total eight are down below and largest of 
all. These creatures have their strongest feet down 
below, just as quadrupeds have their strongest limbs 
at the back ; and the reason is that they carry the 
weight of the body and they chiefly are responsible 
for locomotion. The two outer feet are larger than 
the inner ones because they have to help the others 



685 a 


ndSa? uev ovv iravra tyovoi ravra oktlo, dAA' 
at fjiev or\Tilai /cat at revdlSes jSpa^et?, ra Se 
7To\v7To§d>§7] fieydXovs. to yap kvtos tov atofiaTos 
25 at fiev fieya e^ovatv ra 1 Se /xt/cpdV, ojore rots uev 


Trohwv TTpoaiQrjKev f) envois, rats S* 6l7t6 tojv 
77oha)v Xafiovaa to crcuua r)v^7]0€V, hiorrep rots 
[lev ov piovov irpos TO velv xp-^crtuot ot 77oSes dAAd 
/cat irpos to /?aSt£etiA, Tat? 8' dxprjoTOt' fiLKpol yap, 

so to Se kvtos (liya exovav. iirel Se /?pa^et9 e^ouot 
rovs iroSas /cat axprjGTovs irpos to dvTtAa^Sdvea#at 
/cat firj diroairaoB 'at 2 duo tcov ireTpwv, otov kXvSojv 
fj /cat /cat irpos to Ta diroOev irpoodyeodat, 

Std Ta#Ta irpofiooKihas e^ouat Suo aa/cpd?, at? 

35 oppiovoi T€ /cat d'7700'aAeuoL'O'a' ajairep irXolov otov 

685 b X €l L L dlV fj, /Cat TCL GiTTodeV 07]p€VOVGL /cat TTpoodyovTai 

tclvtclis at T6 GrjirlaL /cat at TevdlSes. ot Se 7roAu- 
TroSes 1 ou/c €)(ovat Tas irpofioGKioas Std to tous" 
TToSa? a^TotS" etVat irpos TauTa xP r i°^ ov ^ * eVtot? 3 
Se /coTuA^Sove? 7700? Tot? 7rocrt /cat 7rAe/cTavat 
6 TTpoaeiGi, Bvvapnv exovaai 4, /cat ovvdeoiv TOtavTTjv 
olavrrep Ta irXeyfiaTLa ot? ot taTpol ot dp^atot tow? 
Sa/cruAous eVe/5aAAov ovtoj /cat e/c tojv tVaiv 

1 ra Peck : 01 vulg. 
* airooTraaOai Bekker : avriOTT&oOai codd. 
3 ivioLS Peck : oaoi? vulg. 
* e^ouaat P : e^ovai vulg. 

The use of these aavpat or aeipat is described by Hippo- 
crates, Ile/n apBpcov (Littre iv. 318-320 ; L.C.L. iii. 390 : " The 
tubes woven out of palm-tissue are satisfactory means of 


in performing their duty. In the Octopuses, however, 
the four middle feet are the biggest. 

And although all these creatures have eight feet, 
the Sepia's and the Calamary's are short ones, since 
their bodies are large in the trunk, and the Octopus's 
feet are long, because his body is small. Thus in 
one case the substance which she took from the body 
Nature has given towards lengthening the feet, and 
in the other she has taken away from the feet and 
made the body itself bigger. Hence it results that 
the Octopuses have feet which will serve them for 
walking as well as for swimming, whereas the other 
creatures' feet will not do so, being small, while the 
body itself is big. And inasmuch as these creatures' 
feet are short, and useless for holding on tightly to 
the rock in a storm when there is a strong sea running, 
or for bringing to the mouth objects that are at a 
distance, by way of compensation they have two long 
probosces, with which during a storm they moor 
themselves up and ride at anchor like a ship ; there- 
with also they hunt distant prey and bring it to their 
mouths. These things the Sepias and Calamaries 
do. The Octopuses have no probosces because their 
feet serve these purposes. Some creatures have 
suckers and twining tentacles as well as feet : these 
have the same character and function as well as the 
same structure as those plaited tubes which the early 
physicians used for reducing dislocated fingers.* 1 They 
are similarly made out of plaited fibres, and their 

reduction, if you make extension of the finger both ways, 
grasping the tube at one end and the wrist at the other." 
The aavpa was thus a tube open at both ends. A similar 
passage in Diocles ap. Apollonius of Kitium, no doubt taken 
from Hippocrates, refers to " the oetpat which children plait " 
(L.C.L. iii. 453). 



685 b 

7T€77Aey/xeVat etcrtV, /cat 1 cXkovgl ra aapKta /cat 
ra ivhcoovra. 7reptAa/x/?dVet fxev yap ^aAapa. ovra* 
orav Se Gwrelvrj, 77te'£et /cat e^eTat tou ivros 
Otyydvovros rravros* 
10 ^Qot' e7Tet aAAo ou/c eortv cS 7Tpood£ovrai, dXX 
?) ra /xev rots' 77oat ra Se rals rrpo^ouKiOL, ravras 
€)(ovgi 7rpos dXKTjv /cat tt]v dXXrjv fiorjdeiav 2 dvrl 

Ta fxev ovv dXXa oik6tvX& ion, yivos Se rt ttoXv- 


rorrjg rrjs <f>voews avrow fiovoKorvXov yap avay- 
15 Kaiov etvat to orevov. ovk ovv ws fiiXriarov e^oucrty, 
aAA' cos" avayKaiov oia rov t'Stov Aoyov rrjs ovoiag, 

Urepvyiov 8' k\ov at ravra rrdvra kvkXw rrepl to 
/cutos*. rovro 5' em /Ltev Tajy aAAajy ovvaTrrofievov 
/cat aw6j(6j eVrt, /cat eVt raiv fieydXwv rev6wv 
at S' eAaTTOUs* /cat /caAou/xevat revdtoes nXarvrepov 

20 T€ TOVTO k^OWl /Cat OU CTT6VOV, WG7T€p at GT]77iaL 

Kal oi 77oAu77o8es*, /cat tout' a770 \xioov rjpypLevov, 
/cat oi) ku/cAoj Sta navros. rovro S' €\ovgiv 

OTTCOS vlwGl /Cat 77/30$- TO OlOpdoVV , WG7T€p TOt? jJL€V 
TTT7]V01S TO SppOTTVyiOV, TOt? 8' L^OvGL TO OVpaiOV. 

iXdxLGrov Se rovro /cat 77/ctcrTa imBrjXov rocs 

25 TToXvTTOGLV €OTt Sta TO (ILKpOV k\eLV TO /CUTO? /Cat 

htopdovodai rots ttoglv iKavws- 

Ylepl fxkv ovv rwv ivrofxwv /cat fiaXaKoorpaKWV 
Kal oGrpaKohipjxojv Kal /xaAa/ctajv etprjrai, Kal 
7repl rwv ivros fJLoplwv Kal rwv eKros. 

so X. IlaAtv 8' e'£ VTrapxrjs Trepl rwv ivaifxwv Kal 

1 Acal Ogle : afc vulg. 
2 aAA^y xP e ^ av Ka%L fiorjdeiav Y, Ogle. 



action is to draw flesh and yielding substances, as 
follows. First they encircle the object while they 
are still relaxed ; then they contract, and by so doing 
compress and hold fast the whole of whatever is in 
contact with their inner surface. 

So, as these creatures have nothing else with which 
to convey objects to the mouth except the feet (in 
some species) and the probosces (in others), they 
possess these organs in lieu of hands to serve them 
as weapons and generally to assist them otherwise. 

All these creatures have two rows of suckers, except 
a certain kind of Octopus, and these have only one, 
because owing to their length and slimness they are 
so narrow that they cannot possibly have another. 
Thus they have the one row only, not because this 
arrangement is the best, but because it is necessitated 
by the particular and specific character of their being. 

All these animals have a fin which forms a circle 
round the sac. In most of them it is a closed and con- 
tinuous circle, as it is in the large Calamaries (teuthi), 
while in the smaller ones called teuthides it is quite 
wide (not narrow as in the Sepias and Octopuses), 
and furthermore it begins at the middle and does not 
go round the whole way. They have this fin to 
enable them to swim and to steer their course, and 
it answers to a bird s tail-feathers and a fish's tail- 
fin. In the Octopuses this fin is extremely small and 
insignificant because their body is small and can 
be steered well enough by means of the feet. 

This brings to an end our description of the internal 
and external parts of the Insects, the Crustacea, the 
Testacea, and the Cephalopods. 

X. Now we must go back and begin again with 




Xolttcov kclI TTporepov elprjjjLevcov {xoplcov tovtlov Se 
StopiaOevTCov irepl tcov ivatficov Kal cootokcov tov 
avrov rponov ipovfiev, 

Ta fiev ovv fiopia ra nepl Tr)v Ke<j>aXr)v tcov ^cpiov 
35 €Lp7]rai rrporepov, Kal to, Trepl tov KaXovpievov 
av)(€va Kal Tpdx^jXov. 6^€t oe K€<f>aXr)v navra ra 
Q86 a evacfia £a>cr tcov S' dval\icov evlois doiopiGTOv 


ra [lev ^cpoTOKa udvT €.x ei » TCOV ^' 4 )0ro ' KCOV T< * 

pi€V €X €L T " ^ OVK *X €l ' ° aa ^ V 7^9 TTVeVjJLOVCL 

5 e^€t, Kal avx^va ex el > T ° L ^ l^V dvairveovTa OvpaOev 

OVK €^€fc TOVTO TO [XOplOV. 

"Ectti S' r) [lev KetbaXr) juaAtara tov iyK€(f)dXov 
xdpiv dvdyKrj yap tovto to piopiov ex €lv ro ^ 
allocs, f<al ev dvTiKeifiivq) tottco Trjs Kapolas, 
Sta, ra? elprjfjievas irpoTepov afolas. e^iBeTO S' i) 
10 chvuis iv avTfj Kal tcov alaOrjaecov evlas Sta to 
GVpifieTpov etvai tyjv tov atfiaTos Kpaocv Kal em- 
Trjoecav rrpos T€ ttjv tov iyK€(f>dXov dXeav Kal 
TTpos TTjV tcov alaOrjaecov rjavx^CLV Kal aKplfieiav. 

€TL Se TpLTOV [JLOplOV VTli§r)Ke TO TTjV T7}S TpOtf>Tj£ 

ecaoSov hrjpLiovpyovv evTavda yap vrreKeiTO ov\i- 
pLtTpcos juaAtcrra* ovTe yap dvcoOev KelaOat Trjs 
is Kaphias Kal Trjs dpxrjs eveoix eTO Tr ) v KoiXiav, ovt€ 
KaTwOev ovarjs ov Tpo-nov e^et vvv eVeSe^eTO ttjv 
eloooov en KaTCo etvai Trjs KapSlas' ttoXv yap av 1 
to firjKos rjv tov acbfxaTos, Kal noppco Xiav Trjs 
KLVovarjs dpxrjs Kal 7T€ttovgt]s. r) jiev ovv K€tf>aXr) 

TOVTCOV X^P lV ZGTWy ° S' CLVxty Trjs dpTTJpLaS X^P lV ' 
1 av P, om. vulg. 



the blooded viviparous animals. Some of the parts 
which we have already enumerated still remain to 
be described, and we will take these first. This 
done, we will describe similarly the blooded Ovipara. 

We have already a spoken of the parts around the External 
head, and what is called the neck, and the throat. bloode°d 
All blooded animals have a head, but in some of the animals. 
bloodless ones the head is indistinct (e.g. in crabs). (a)Vlvipar * : 
All Vivipara have a neck, but not all Ovipara : to 
be precise, only those which breathe in air from with- 
out and have a lung. 

The presence of the head is mainly for the sake of Head and 
the brain. Blooded creatures must have a brain, 
which (for reasons aforeshown) b must be set in some 
place opposite to the heart. But in addition, Nature 
has put some of the senses up in the head, apart from 
the rest, because the blend of its blood is well pro- 
portioned and suitable for securing not only warmth 
for the brain but also quiet and accuracy for the senses. 
There is yet a third part which Nature has disposed of 
in the head, viz. the part which manages the intake 
of food ; it was put here because this gave the best- 
ordered arrangement. It would have been impossible 
to put the stomach above the source and sovereign 
part, the heart : and it would have been impossible 
to make the entrance for the food below the heart, 
even with the stomach below the heart as it actually 
is, because then the length of the body would be 
very great, and the stomach would be too far away 
from the source which provides motion and concoc- 
tion. These then are the three parts for whose sake 
the head exists. The neck exists for the sake of the 

« At 655 b 27—665 a 25. b At 652 b 17 ff. 



20 TTpofiXypLa yap €gtl, Kal goj^l ravT7)V Kal tov oIgo- 
(j)dyov kvkXoj Trepiiyojv . tols fiev ovv dXXoLS ion 


Xeovres \lovogtovv tov avylva typvGiv. efiXei/je 
yap 7) (f>VGis 07tcos Trpos tt)v Igxvv xP^ Gl l Ji0V avTOV 
ZyaiGi piaXXov rj Trpos tols dXXas fiorjdeCas. 

'E^d/xeva &€ tov avx^vos Kal rrjs K€(f>aXrjs rd re 
25 TTpoodia KwXa tols ^(pOLs ecrrt Kal dojpat;. 6 fiev 

OVV avdpCDTTOS OLVTi GKtXwV Kal 77 oh <LOV TO)V 7TpOG6loJV 

fipaxiovas Kal tols KaXovjxivas ^X €l X e ^P a ^* opOov 
(lev yap Igti \iovov to>v ^coojv Sia to ttjv <f>vGLV 
avTOv Kal tt]v ovGiav tivai Oelav epyov Se tov 


so ttoXXov tov avcoOev imKeifxivov GOjfiaTOS' to yap 


kolvtjv aLG0TjGLv . Sto TrXeiovos yivofxevov tov 
fidpovs Kal tov GCDfxaTcodovs dvdyKrj pinaiv ra 
GOjfiaTa Trpos TTjv yrjv > ojgtz Trpos ttjv dcr^aAetar 
avTl fipaxLovcov Kal x^ l P^ v tovs TrpoG0LOVS TroSas 

35 V7T€dr]K€V T) <f)VGL$ TOtS" TZTpdllOGlV . TOVS p<€V 

686 b yap ottlgBlovs Suo iraGiv dvayKaiov tols iropev- 
tlkols €X €lv > T( * ^ 'TOLavTa T€Tpa77oha lyiveTo ov 
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vava>Ses yap Igtiv ov to jjlIv ava> \xiya, to Se 

6 (f>€pOV TO fidpOS Kal 7T€^€VOV fJLLKpOV dvO) 8 €GTLV 

6 KaXovfievos dojpat;, diro ttjs K€(f>aXrjs ^XP l T ^ s ' 

For the " general " or " common " sense see De mem. 
450 a 10, etc. ; and cf. De part. an. 656 a 28, 665 a 12. The 
" general " sense is not another sense over and above the 
ordinary five, but rather the common nature inherent in 


windpipe : it acts as a shield and keeps the windpipe 
and the oesophagus safe by completely encircling 
them. The neck is flexible and has a number of 
vertebrae in all animals except the wolf and the lion 
whose neck consists of one bone only, for Nature's ob- 
ject was to provide these with a neck that should be 
useful for its strength rather than for other purposes. 

The anterior limbs and the trunk are continuous Limbs, and 
with the head and neck. Man, instead of forelegs relative 
and forefeet, has arms and hands. Man is the only sizes - 
animal that stands upright, and this is because his 
nature and essence is divine. Now the business of 
that which is most divine is to think and to be intelli- 
gent ; and this would not be easy if there were a great 
deal of the body at the top weighing it down, for 
weight hampers the motion of the intellect and of the 
general sense. a Thus, when the bodily part and the 
weight of it become excessive, the body itself must 
lurch forward towards the ground ; and then, for 
safety's sake, Nature provided forefeet instead of 
arms and hands — as has happened in quadrupeds. 
All animals which walk must have two hind feet, and 
those I have just mentioned became quadrupeds be- 
cause their soul could not sustain the weight bearing 
it down. Compared with man, all the other animals 
are dwarf-like. By " dwarf-like " I mean to denote 
that which is big at the top {i.e. big in the " trunk," 
or the portion from the head to the residual vent), 
and small where the weight is supported and where 

them all ; thus Aristotle (De somno) argues that their simul- 
taneous inactivity during sleep is not a mere coincidence but 
is due to the inactivity of the central perceptive faculty of 
which they are differentiations. Among the functions of the 
" general " sense are : discrimination between the objects of 
two senses, and the perceiving that we perceive. 



688 b 

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vavrlov rd [jl€v dvw fxeydXa, ro Se Kara) piiKpov 

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rd jxev ovv [xwvvxa Kal St^TjAa rovrov e'^ei rov 
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/xeV lariVy rjrrov Se rovrwv Sto Kal rr)v av^rjcriv 

20 irpds rd dva) rd Kara) Kara Xoyov Troietr at rrjs 
iXXeiipews . 

v E(7Tt Se Kal ro rwv opvidwv Kal rd rwv l^Qvaov 
yivos Kal rrav ro evatfiov, wenrep etprjraL, vavwSes. 
Si6 Kal d<f>poi'€or€pa rrdvra rd £a)a rcov dvdpwrrwv 
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25 vavwheis rrjv tf>VGiv 3 idv /cat riv* dXXrjv Svvapuv 
e^wui irepirrrjVi aXXd rw rov vovv e^eiv cA- 
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r) rrjs ifivxys &PXV noXAots Srj 1 ovoKivrjros icrri 
Kal awfiarworjs . ere 8' iXdrrovos yivofievrjs rrjs 

1 7roAAoiy hrj Peck : ttoXXu) Srj vulg. : add. Kal Y, Piatt, qui 
et insilper addit (jSapa acofiart Kara<f>€po^€V7j). 


locomotion is effected. In man, the size of the trunk 
is proportionate to the lower portions, and as a man 
grows up it becomes much smaller in proportion. 
In infancy the reverse is found : the upper portion is 
large and the lower is small (and that is why infants 
cannot walk but crawl about, and at the very be- 
ginning cannot even crawl, but remain where they 
are). In other words, all children are dwarfs. Now, 
in man, as time proceeds, the lower portion grows : 
Not so with the quadruped animals : their lower 
portion is biggest at the beginning, and as time 
proceeds the top portion grows (i.e. the trunk, the 
portion between the head and the seat). Thus foals 
are quite or almost as high as horses, and at that age a 
foal can touch its head with its hind leg, but not when 
it is older. a What has been said holds good of the 
animals that have solid hoofs or cloven. The poly- 
dactylous, hornless animals are indeed dwarf-like 
too, but not so markedly, and so the growth of their 
lower portions compared with the upper is propor- 
tionate to the smaller deficiency. 

The whole groups of birds and fishes are dwarf-like ; 
indeed, so is every animal with blood in it, as I have 
said. This is why all animals are less intelligent than 
man. Even among human beings, children, when 
compared with adults, and dwarf adults when com- 
pared with others, may have some characteristics in 
which they are superior, but in intelligence, at any 
rate, they are inferior. And the reason, as afore- 
said, is that in very many of them the principle of the 
soul is sluggish and corporeal. And if the heat which 

a These observations are entirely correct. Cf. Ogle's 
quotation ad loc. from T. H. Huxley. See also Hist. an. 
500 b 26 ff. 




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677* d'/coot? ylverai tols rrTopQois- 

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fxel^ovi, Kal KvptojTepq) TTpoaeOrjKe rovXarrov , dAA' 

15 OV T<2> cAaTTOW TO TLfJLld)T€pOV Kal fiel^ov. €1 ovv 

ovtojs fieXnov, rj he <f>vois eK tcov evhexopievojv 

a With the terminology used in 11. 28-29 cf. Hippocrates, 
Uepl Biairi]?, i. 35. 

b That is, it answers to residue in animals ; c/. 655 b 35. 


raises the organism up wanes still further while the 
earthy matter waxes, 3 then the animals' bodies wane, 
and they will be many-footed ; and finally they lose 
their feet altogether and lie full length on the ground. 
Proceeding a little further in this way, they actually 
have their principal part down below, and finally the 
part which answers to a head comes to have neither 
motion nor sensation ; at this stage the creature 
becomes a plant, and has its upper parts below and its 
nether parts aloft ; for in plants the roots have the 
character and value of mouth and head, whereas the 
seed counts as the opposite, 5 being produced in the 
upper part of the plant on the ends of the twigs. 

We have now stated why it is that some animals 
have two feet, some many, some none at all ; why 
some creatures are plants and some animals ; and 
why man is the only one of the animals that stands 
upright. And since man stands upright, he has no 
need of legs in front ; instead of them Nature has 
given him arms and hands. Anaxagoras indeed 
asserts that it is his possession of hands that makes 
man the most intelligent of the animals ; but surely 
the reasonable point of view is that it is because he 
is the most intelligent animal that he has got hands. 
Hands are an instrument ; and Nature, like a sen- 
sible human being, always assigns an organ to the 
ariimal that can use it (as it is more in keeping to 
give flutes to a man who is already a flute-player 
than to provide a man who possesses flutes with the 
skill to play them) ; thus Nature has provided that 
which is less as an addition to that which is greater 
and superior ; not vice versa. We may conclude, then, 
that, if this is the better way, and if Nature always does 
the best she can in the circumstances, it is not true 



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2 ex ov e * corr. U : e^cov vulg. 
3 ottov av] ottotov Ogle. 
4 ^X €lv CLV-njv P : Zx €LV ' f&vvfl ^ulg* 
^'xwiifLCfxrjxdviiTai Ogle : avfjifxefirjxavrjaOou vulg. 
6 €tSo$ koI vulg. : etSo? PSUYZ. 



to say that man is the most intelligent animal because 
he possesses hands, but he has hands because he is the 
most intelligent animal. We should expect the most 
intelligent to be able to employ the greatest number 
of organs or instruments to good purpose ; now the 
hand would appear to be not one single instrument 
but many, as it were an instrument that represents 
many instruments. Thus it is to that animal (viz. 
man) which has the capability for acquiring the 
greatest number of crafts that Nature has given that 
instrument (viz. the hand) whose range of uses is the 
most extensive. 

Now it must be wrong to say, as some do, that 
the structure of man is not good, in fact, that it is 
worse than that of any other animal. Their grounds 
are : that man is barefoot, unclothed, and void of 
any weapon of force. Against this we may say 
that all the other animals have just one method of 
defence and cannot change it for another : they are 
forced to sleep and perform all their actions with 
their shoes on the whole time, as one might say ; 
they can never take off this defensive equipment of 
theirs, nor can they change their weapon, whatever 
it may be. For man, on the other hand, many 
means of defence are available, and he can change 
them at any time, and above all he can choose w T hat 
weapon he will have and where. Take the hand : 
this is as good as a talon, or a claw, or a horn, or again, 
a spear or a sword, or any other weapon or tool : 
it can be all of these, because it can seize and hold 
them all. And Nature has admirably contrived the 
actual shape of the hand so as to fit in with this 
arrangement. It is not all of one piece, but it 
branches into several pieces ; which gives the possi- 



evi yap iv rep oiaiperrjv elvai Kal GvvOerrjv etvat, 

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20 XapL^avoptevov dvdyKT] irepiXapifidveGdai kvkXco 
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KaXetrat ^teyas fiLKpos cov, on d^o^orot cos 
elrreiv ot dAAot avev rovrov. ev oe Kal ro rcov 
ovvxojv piejJLrjxdvrjrai' rd [lev yap aXXa £a>a k'xei 
/cat rrpos XPV°' LV civrovSj rots S* dvQpcorrois em- 

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At Be Kafirral rcov fipaxtdvcov k'xovGi rrpos re 
rr)v rrjs rpo<f>rjs rrpoGaycoyrjv Kal rrpos ras d'AAas 
XprjGeis evavrlcos rocs rerpdiroGiv. eKelvois fiev 
yap dvayKalov eloco Kapmreiv rd efirrpoGdia KcoXa 
(xpcovrac yap cbs z ttoglv) tV rj ^p^ot/xa rrpos rrjv 

1 eVt] fiia Ogle. 
2 /xecrdvecoff Schneider : /xecrov recoj vulg. 
3 cos P, om. vulg. 

° That is, the pieces. Ogle's suggested emendation 
would be translated " use the hands singly." The two 
transpositions suggested for this passage by Ogle seem un- 


bility of its corning together into one solid piece, 
whereas the reverse order of events would be im- 
possible. Also, it is possible to use them a singly, or 
two at a time, or in various ways. Again, the joints 
of the fingers are well constructed for taking hold 
of things and for exerting pressure. One finger is 
placed sideways : this is short and thick, not long 
like the others. It would be as impossible to get 
a hold if this were not placed sideways as if no hand 
were there at all. It exerts its pressure upwards 
from below, whereas the others act downwards from 
above ; and this is essential for a strong tight grip 
(like that of a strong clamp), so that it may exert 
a pressure equivalent to that of the other four. It 
is short, then, first, for strength, but also because it 
would be no good if it were long. (The end finger 
also is small — this is as it should be — and the middle 
one is long like an oar amidships, because any object 
which is being grasped for active use has to be 
grasped right around the middle.) And on this 
account it is called " big" although it is small, be- 
cause the other fingers are practically useless without 
it. The nails, too, are a good piece of planning. In 
man they serve as coverings : a guard, in fact, for the 
tip of the fingers. In animals they serve for practical 
use as well. 6 

The joints of the arms in man bend in the opposite 
direction to those of quadrupeds : this is to facilitate 
the bringing of food to the mouth, and other uses to 
which they are put. Quadrupeds must be able to 
bend their fore limbs inwards c so that they may be 
serviceable in locomotion, since they use them as 

6 That is, as tools. 
e See note on 693 b 3, p. 433. 



687 b 

so Trope lav, eVet QeXeL ye /cd/ce lvojv tols 7roXvhaKTvXois 


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tols JjLev appeoL Std ttjv elprjpevrjv air lav, iirl he 
1 TrejjLTrros seclusi. 



feet ; though even among quadrupeds the poly- 
dactylous ones tend to use the fore limbs not only for 
locomotion but also instead of hands ; and this can 
actually be seen happening : they take hold of things 
and defend themselves with their fore limbs. (Solid- 
hoofed animals, on the other hand, do this with their 
hind limbs, as their forelegs have nothing that corre- 
sponds to elbows and hands.) This explains why 
some polydactylous quadrupeds actually have five 
toes on their forefeet (lions, wolves, dogs and leo- 
pards, for instance), although there are only four on 
their hind feet : the fifth one, like the fifth a digit 
on the hand, is a " big " one. & However, the small 
polydactylous quadrupeds have five toes on their 
hind feet too, because they are creepers ; and this 
gives them more nails, and so enables them to get a 
better hold and creep up more easily to greater 
heights and above your head. 

Between the arms in man (in other animals be- Breast 
tween the forelegs) is what is known as the breast. In 
man the breast is broad, and reasonably so, for the 
arms are placed at the side and so do not in any way 
prevent this part from being wide. In the quadru- 
peds, however, it is narrow, because as they walk 
about and change their position the limbs have to be 
extended forwards. And on this account, in quadru- 
peds, the mammae are not on the breast. In man, 
on the other hand, as the space here is wide, and the 
parts around the heart need some covering, the 
breast is fleshy in substance and the mammae 
are placed on it and are distinct. In the male they 
are themselves fleshy for the reason just given. In 

° Now generally called the " first.'* 
b And needed when the foot is used as a hand. 



688 a 

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yap av irpos tt)v 7Topelav) ) e'xovaL 8' rjSr) 770AA0US' 
Tpoirovs. 3 tcl fxev yap oXiyoTOKa Kal [Hjovvya Kal 
KepaTocj)6pa ev tols firjpoLs e^ovai tovs fiaaTOVs, 

Kal TOVTOVS SvO, TCL Se TroXvTOKa 7) 7ToXvO)(tdfj TCL 

35 fiev irepl TTjV yauTepa irXaylovs Kal iroXXovs, olov 
688 b £$• Ka l KvwVy tcl Se Svo fiovovs, irepl [leorjv fievTOL 
yaoTepa, olov Xea>v. tovtov 8' o!ltlov ovx otl 
oXiyoTOKOV, errel tlktcl iroTe TrXeloj Svolv } aAA' oti 
ov 7ToXvydXaKTov avaXiGKei yap els to acofia Tr)v 
XafJL^avofievrjv Tpo<f)rjv 3 XafifidveL Se urrdvLov Sia to 
5 aapKocf)dyov elvat,. 

'0 S 3 eXecfras Svo \16vov e\ei } tovtovs S' viro Tats 
fiaoxdXais twv ifiirpoaOlwv GKeXwv. atVtov Se tov 
[lev Svo e\eiv oti jjlovotokov €otl } tov Se firj ev tols 
{xrjpoXs otl noXvax^Ses (ovSev yap €^et iroXvoxtSes 
ev to?s psQpois), OLVd) Se irpos Tals /xao^aAats', 

1 aAArJAa? Bekker per typothetae errorem. 
2 J} xa^-rrov P : \11lg. non habet. 
3 fort, tottous Rackham (sic etiam E teste Buss, et Z). 


the female, Nature employs them for an additional 
function (a regular practice of hers, as I maintain), 
by storing away in them nourishment for the off- 
spring. There are two mammae because the body 
has two parts, the right and the left. The faet that 
they are somewhat hard and at the same time two in 
number is accounted for by the ribs being joined to- 
gether at this plaee and by the nature of the mammae 
not being at all burdensome. In other animals it is 
either impossible or difficult for the mammae to be 
situated upon the breast, i.e. in between the legs, 
since they would be a hindrance to walking ; but, ex- 
cluding that particular position, there are numerous 
ways in which they are placed. Animals whieh have 
small litters, both those that have solid hoofs and those 
that carry horns, have their mammae by the thighs ; 
and there are two of them. Animals that have large 
litters or are polydaetylous, either have numerous 
mammae placed at the sides upon the abdomen — 
e.g. swine and dogs ; or have only two, set in the middle 
of the abdomen — e.g. the lion. a The reason for this is 
not that the lion has few cubs at a birth, beeause 
sometimes the number exeeeds two, but that it is 
deficient in milk. It uses up all the food it gets upon 
the upkeep of the body, and as it is a flesh-eater it 
gets food but rarely. 

The elephant has only two mammae (this is because 
it has its young one at a time), and they are under the 
axillae of the forelegs and not by the thighs beeause 
the elephant is polydaetylous and no polydaetylous 
animal has them there. They are high up, near the 
axillae, beeause that is the plaee of the foremost 

° This, like many of Aristotle's statements about the lion, 
is incorrect. 

n 379 



fxaarovg, Kal ifiajvrai ydXa itXzlgtov. arjpetov 
he to irrl ra>v vu>v ovp,f3aXvov rots yap rrpwrois 
yevopLevoLS tojv x°^P 0JV tovs irpcoTOVS 7raplx oV(Jl 


loTiy tovtoj tovs pbaoTOVs dvayKalov k'xeLV tovs 
TrpwTOVs' 7Tpa>TOi 8' elolv oi viTO Tals paoxdXaLS . 
15 o p,ev ovv iXicfxxs 8ia tglvti]v ttjv air lav hvo e^ei 

Kal iv TOVTOJ T(X> T07TW, TCL 8e TToXvTOKa 7T€pl TTJV 

yaoTepa. tovtov 8' aLTLov otl uXeLovojv Set p*a- 
otojv tols TrXelco fieXXovaiv ckt pecbetv ■■ iirel ovv IttI 
nXaTos ovx olov T€ dAA' rj hvo pLovovs €.X eiv ^ t( * T0 
hvo eivai to t dpLUTepov Kal to Sefidv, irrl pbrjKos 
20 dvayKalov €X €LV ' ° Se fi€Ta£v touos tojv eparpooOev 
OKeXwv Kal tojv OTTLoOev e^ei prjKos povov. to. 
&e jjiTj 7toXvox l ^V aAA* oXiyoTOKa rj K€paTO(f>6pa iv 1 

TOLS pLTjpOLS €)(€l TOV? pLaOTOVS y olov XtTTTOS , OVOSy 

Ka(.L7]Xos (TavTa ydp [.lovoTOKa, Kal to, {lev pLojvvx&, 
25 to he St^Aov), €tl 8' eXacj)os Kal ftovs Kal atf Kal 
TaXXa TrdvTa rd TotavTa. cutlov 8' oti tovtols 
rj av^rjoris €77 1 to dvoj tov uojpaTos Iutlv. waO^ 
07tov avXXoyrj Kal TiepLovola ylveTaL tov uepLT- 
rojptaTos Kal aipaTOs (ovtos 8' 6 tottos icrrlv 6 
/cara> Kal uepl tols eKpods), evTavOa eTrolrjaev r) 
<j>vais tovs pcacrTovs' ottov yap Kivqais ylveTai ttjs 
30 Tpo<f>rjSj evTevOev Kal Xafielv eonv avTols hvvaTov. 
avOpojTTOs fiev ovv Kal 6 OrjXvs Kal 6 dpprjv e^et 
piaoTovs, iv he tols dXXois evLa tojv dppevojv ovk 

€^€t, OLOV 1777701 01 peV OVK k'xOVOLV ol 8* k^OVGLV , 

1 Kal iv vulg. : Kal del. Ogle. 



mammae in those that have many, and these are the 
ones that yield the most milk. An illustration of 
this is the case of the sow : a sow will offer the 
first of its mammae to the first ones of the litter. 
Thus, where the first of an animal's litter amounts 
to one and no more, such an animal must possess 
these first mammae, and " the first mammae " means 
those under the axillae. This explains, then, the 
number and position of the elephant's mammae. 
The animals that have large litters have their mammae 
upon the abdomen. Why is this ? They have 
numerous young to feed, and so they need numerous 
mammae. Now as the body has two sides, right and 
left, the mammae cannot be more than two deep 
across the body, and so they have to be disposed 
lengthwise, and the only place where there is suffi- 
cient length for this is between the front and hind 
legs. Non-polydactylous animals which yet produce 
few at a birth, or carry horns, have their mammae by 
the thighs, as the horse and the ass (both solid- 
hoofed) and the camel (cloven-hoofed), all of which 
bear their young singly ; also the deer, the ox, the 
goat, and all such animals. The reason for which is, 
that in them the growth of the body proceeds in an 
upward direction ; so the place where the superfluous 
residue and blood collects is down below, near the 
places of efflux, and there Nature has made the 
mammae ; for where the food is set in motion, there 
is the very place where they can get it. In man, both 
male and female have mammae, but some males of 
other animals have none, as e.g. stallions, some of 
which have none, while others, which resemble their 
dams, have them. 



Kat rrepl fiev [.lauTajv €ipr]rai y (xera he to arrjOog 
35 6 rrepl ttjv KotXLav iorl t6ttos } auvyK.Xe lotos tols 
689 a rrXevpalg Sta tt\v elprjfievrjv epLrrpooOev atnav, 
orrtog fxr} <EjU7ToS/£a>cri (jltjt€ ttjv avoiSrjoiv Trjg 
Tpocf>fjs, rjv avayKoiov avufialveiv Oepiiacvofievrig 
avrfjg, f-f]T€ Tag varepas Tag irepi tt\v Kvrjotv. 
TeXog ok tov KaXovjjievov OwpaKog euTi tol [JLOpca 

6 tol rrepl tt)v Trjg rrepiTTwoewg e^ohov, Trjg re £r]pag 
Kal Trjg vypag. /caTa^p^rat §' rj (f>vacg toj avTw 
fjLopla) €77i T€ TTjv Trjg vypag e£o$ov rrepiTTwaeojg 
Kal 7T€pl Tr)v o^etW 3 ofioioog ev T€ Tolg OrjXecn Kal 
Totg dppeatv, 1 e£a) tlvwv oXlywv rraoi Tolg evaifioig, 
ev Se Tolg ^woTOKOig rraoiv. aiTiov 8' oti t) yovr) 

10 vypov eart tl Kal rrepLTrwfia. (tovto oe vvv fxev 
v7TOK€io9a) t VGTepov oe. SeixOrjaerat rrepl avTov.) 
tov avTov he Tporrov Kal ev Tolg OrjXeaL ra T€ 
KaTafjL-qviaj Kal fj rrpotevTai Trjv yovrjv 2 - hioptadrj- 
aeTac oe Kal rrepl tovtcov vuTepov, vvv §' vrroKel- 
oQoj jxovov oti rrepiTTCojjLa Kal to. KaTapLrjVLa Tolg 

is OrjXeotv' vypa he ttjv (j>vcriv to. KaTapnqvia Kal rj 
yovr] } wore 5 tcov ofiolwv elg tol aura 4 fiopia Tr)v 
eKKpLUiv elvai KaTa Xoyov eorlv. evTog he rrcog 
€yei } Kal rrfj hia<f>epovoi to. tc rrepl to orrepfxa Kal 
tol rrepl Trjv kvtjolv, €K T6 Trjg loTopLag Trjg rrepl 
to. £<£>a <f>avepov Kal twv avaTopioov, Kal voTepov 

20 Ae^&Jaerat ev Tolg -rrepl yeveoeayg. oti §' eyei Kal 

1 rots appeoiv Ogle : tcov appivcov vulg. 
2 Kal el 77-potevrat rtva yoiiqv Piatt. 
3 post wore vulg. habet tcov clvtcov kox : Ogle del. 
4 tlx avTa Peck : tglvto. ra vulg. 



This concludes our remarks on the mammae. 

After the breast comes the region around the 
stomach, which is not enclosed by the ribs for 
the reason stated earlier, viz. to avoid interference 
(a) with the food when it swells, as it must do when 
it is heated, and (b) with the womb during pregnancy. 

At the end of what is called the trunk are the parts Excretory 
that have to do with the discharge of the residue, organ3 * 
both solid and fluid. Nature employs one and the 
same part for the discharge of the fluid residue and 
for copulation in all blooded animals (with a few 
exceptions), male and female alike, and in all Vivipara 
without exception. The reason is that the semen is a 
fluid, and a residue. (This statement may stand for 
the present : the proof of it will be given later on. & ) 
The same applies to the catamenia in females, and 
the part where they emit the semen. c This also will be 
dealt with particularly later on. For the present, let 
the statement stand simply that the catamenia in 
females (like the semen in males) are a residue. Now 
both semen and catamenia are fluids, so it is reason- 
able that things which are alike should be discharged 
through the same parts. A clear account of the 
internal structure of these parts, showing the differ- 
ences between the parts connected with semen and 
those connected with conception, is given in the 
Researches upon Animals d and the Dissections, and 
there will be a discussion of them in the book on 

° At 655 a 2. 

b In De gen. an. 724 b 21 ff. 

c This seems to agree with what Aristotle says on the 
subject in the Hist. An., but contradicts what he says in De 
gen. on. Piatt's suggested emendation would make the 
translation read ; " and to the semen, if so be they emit any." 

d At 493 a 24-b 6, 497 a 24 ff., book iii, ch. 1. 



ra Gyy\\xara tcov \xopicov tovtcov rrpos rrjv ipyaalav 
dvayKalcos, ovk dorjXov, ^X €l ^ Btatpopds to tcov 
dppevcov opyavov Kara ras rov crcopLaTog hiatf>opds. 
ov yap SfjLOLOjg arravra vevpcohr) rrjv <f>v<jtv iarlv. 
en Se fiovov rovro row fiopicov dvev vocrepds fiera- 
25 fioXijs av^rjaiv e^et Kal TairtLVOJoiv tovtcov yap to 
[lev xprjOipLOV irpos t6v GvvhvaapLov, to 8e irpo? ttjv 
tov dXXov aojfxaTos xpeiav del ydp 6}iolcos 'ix ov 
TaAAa 1 iveirooL^ev dv. avvearrjKe oe tt)v cpvaiv 


dfichoTepa avpLfiaiveiv to fiev ydp k'xet vevpwSes 
30 to Se ^oi'SptL>Ses' J OLOirtp uvviivai T€ SvvaTai /cat 


fiev ovv 6r)Xea tcov TtTpairohcov ttovt IutXv otti- 
udouprjTtKa Sta to irpos ttjv o^€tW ovtcos etvai 
avTots xprjcrLfjirjv ttjv diaiv, tcov 8' dppevcov oXLya 
icjTiv oTnudovprjTLKa, olov Xvy^ y Xecov, KafirjXos, 
689 b oacrvrrovs' ficowxov 8' OVO€V iuTLV OTTLCrOoVprjTlKOV. 
Ta 8' oiTLoOev Kal Ta 7T€pl Ta GKiXrj tols dvdpto- 
7701s* toicos e^ei Trpog Ta TeTpdrrooa. KepKov 8' €^ei 
irdvTa ox^oov, ov fiovov Ta ^cooTOKa dXXd Kal Ta 
cboTOKa- Kal yap aV firj fieye9o$ avTolg ^X ov T ^X[f 

5 TOVTO TO flOpLOV, dXXd G7]fl€LOV 3 y* €V€K€V e^OUOX 

Tiva otoXov. 6 8' dvdpcoTTos aKepKov fiev iuTiv, 
Igx^ol 8' e^et, tcov Se TtTpairoocov ovoiv. ctl Be Kal 
Ta CTKeXr] 6 fiev dvBpcorrog oapKcohf] Kal firfpovs Kal 
Kvrjfias* Ta 8' aAAa irdvr dcrapKa e^et, ov fiovov Ta 
^cpoTOKa dAA' oXcos ooa uKeXrj e^et tcov ^cocov 
io vevpcoSrj yap e^ei Kal ourcohr] Kal aKavBcoSrj. 
tovtcov 8' alrta fiia ris ioriv cos €ltt€lv airavTcov, 

1 ex ov T^AAa Peck : e^ovra vulg. 
2 rvxn Rack ham : $ vulg. 



Generation. 0, Still, it is clear that the actual forms of 
these parts is determined of necessity by the function 
they have to perform. The male organ, however, 
exhibits differences corresponding to those of the 
body as a whole, for some animals are more sinewy, 
some less. Further, this organ is the only one which 
increases and subsides apart from any change due 
to disease. Its increasing in size is useful for copula- 
tion, its contraction for the employment of the rest 
of the body, since it would be a nuisance to the 
other parts if it were always extended. And so it 
is composed of substances which make both con- 
ditions possible : it contains both sinew and cartilage ; 
and so it can contract and expand and admits air 
into itself. All female quadrupeds discharge the 
urine backwards, as this arrangement is useful to 
them for copulation. A few males do this (among 
them are the lynx, the lion, the camel, and the 
hare), but no solid-hoofed animal does so. 

The rear parts and the parts around the legs are Rear parta. 
peculiar in man compared with the quadrupeds, nearly 
all of which (Ovipara as well as Vivipara) have a tail, 
which even if it is not of any great size, still is present 
for a token as a sort of stump. Man has no tail, but 
he has buttocks, which no quadruped possesses. b In 
man, the legs, both in thighs and calves, are fleshy : 
in all other animals that have them (not only Vivi- 
para) the legs are fleshless, being sinewy, bony and 
spinous. One might say that there is a single ex- 
planation which covers them all, which is, that man is 

« At 716 a 2—721 a 29. 

b There seems to be something wrong with this statement, 
but perhaps when taken in conjunction with the whole of the 
argument which follows, it may appear less unjustifiable. 

3 OT)li<ziov Buss . : afiiKpov vulg. 4 *o^/xa?] 7roSa? Y. 



OlOTl fJLOVOV 6CTTLV ov ra>v ^cpcov av9pa>7TO$. IV* 
ovv <j>ipD pahiojs rdva) Kov<j>a ovra 3 d(f>eXovaa to 
GQJfiarcooes dird rcov aVaj irpos rd Karco to fidpos 
rj <f>vats 77poGi9rjK€v oioirzp to. tcr^ta GapKcohrj 

15 €7TOtrja€ Kal firjpovs Kal yaGrpoKvrjfiLa^. dfia ok 
rf]v re ra)v layittiv <^vglv Kal irpos ra? dvairavGeis 
d7T€oa>K€ xprjcnpov toT? {jl€V ydp rerpdiroGiv OLKOITOV 
to iardvai, Kal ov KapLvovGi rovro irotovvra ovv- 
e^cDs" (a)G7T€p ydp KaraKetpceva SiareXet vtto- 
K€LpL€vajv rerrdpwv ipeiojidrojv) } rots 8' dvdpdmois 

20 ov pdStov 6p6a)s ioTtooL Siafjieveiv y dXXd oeirai to 
acofia dva7TavG€CL>s Kal KaOeSpas. 6 fxev ovv dv- 
Bpojnos tcr^ta t' e-^et Kal ra gkeXtj GapKdborj Sia 
rrjv elprjfjievrjv alriav, Kal hid ravra aKepKOV (rj 
t€ yap eVetae 1 rpocfyr] rropevopevrj els ravra dva- 
XiGKeraty Kal hid to ^X €lv t- a X*- a dcfrrjprjraL rj rrjs 

25 ovpas dvayKaia XPV G(S )> T ° L ^ rerpdirooa Kal 
raXXa £a>a i£ evavrias' vavtodeGi yap ovgi 7Tp6$ rd 
dvoj to fidpos Kal to GOJfiara)0€s liTLKetrai tt&v, 
d<f>7]prjfj,€vov and rcov KarcuOev hioTrep aviGXia Kal 
GKXrjpd rd gkcXt} exovGiv. ottcos 8' iv (f>vXaKrj Kal 
gkIttji rj to Xetrovpyovv fioptov rrjv e^ohov rov 

30 Trepirrcoparos, rrjv KaXovfjLevrjv ovpdv Kal KepKov 
avrols a77€$a)K€v rj <f>vGLs, d^eXofievr] rrjs els ra 
GKeXrj ytyvofxevrjs rpo<f>fjs. 

( f O Se itlBtjkos oid to rrjv fj,op<f)7jv iirapi^orepL^eiv 
Kal firjoeripoov r elvai Kal dpi^orepojv, oid rovr 
ovr ovpdv e^efc ovr tcr^ta, chs piev olttovs oov ovpdv, 
cos oe rerpdrrovs ta^ta.) 

690 a TcOV 0€ KaXoVfJL€VOJV KepKtOV Oia(f>opai T €IGL 
1 €K€LO€ Peck : eVet vulg. 



the only animal that stands upright. Hence, Nature, 
so as to make the upper parts light and easy to carry, 
took off the corporeal matter from the top and trans- 
ferred the weight down below ; and that is how she 
came to make the buttocks and the thighs and the 
calves of the legs fleshy. At the same time, in 
making the buttocks fleshy, Nature made them useful 
for resting the body. Quadrupeds find it no trouble 
to remain standing, and do not get tired if they 
remain continually on their feet — the time is as good 
as spent lying down, because they have four supports 
underneath them. But human beings cannot remain 
standing upright continually with ease ; the body 
needs rest ; it must be seated. That, then, is why 
man has buttocks and fleshy legs, and for the same 
reason he has no tail : the nourishment gets used up 
for the benefit of the buttocks and legs before it can 
get as far as the place for the tail. Besides, the 
possession of buttocks takes away the need and 
necessity of a tail. But in quadrupeds and other 
animals it is the opposite : they are dwarf-like, which 
means that their heavy corporeal substance is in the 
upper part of them and does not come into the lower 
parts ; and as a result they have no buttocks and their 
legs are hard. Yet to ensure that the part which 
serves them for the discharge of the residue shall be 
guarded and covered over, Nature has assigned to 
them tails or scats by taking off somewhat of the 
nourishment which would otherwise go into the legs. 

(The Ape is, in form, intermediate between the 
two, man and quadruped, and belongs to neither, or 
to both, and consequently he has no tail, qua biped, 
and no buttocks, qua quadruped.) 

There are numerous differences in the various tails, 



TrXelovs Kal rj envois TTapaKaTaxprjrai Kal em rov- 


dXXa Kal Trpos cbcpeXetav Kal xprjuiv tols exovoiv. 
5 Ot oe ttoScs tols p.ev rerpdrroai Sta</>e pov o iv ra 
fiev yap \xd>vvya avrcov £gti tcl oe St^Aa ra oe 
7ToXvox^rj, \xd>wyxL \xev ogols Sid fieyeOos Kal to 
ttoXv yecoSes ix elv ^- VT ^ KzpaTOiv Kal ooovtojv els 
rrjv rov ovvxos <f>vGiv to tolovtov [Aopiov eXafiev 
iiroKpioiVj Kal Sid ttXtjOos dvrl TrXetovcov ovvxojv 
10 els ovv£ rj oTrXtj iariv. Kal aGTpdyaXov Be Sid 

TOVTO OVK k^OVGLV COS €7tI TO TToXl) €L7T€LV , Kal Sid* 

to SvGKLvrjTorepav etvat rrjv Kafnrrjv tov ottlgQev 
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Kal /cAeieTtu Ta fiiav ex ovra ycovlav rj irXelovs, 6 
S' aGTpdyaXos yoficpos cov coGirep dXXoTpLOV kcoXov 

15 e/xjSe/jA^Tai Tots' ovgl, fidpos pi€V 77ap£x ov > ttoiovv 
S' aGcpaXeGrepav ttjv fiaGcv. Sid yap tovto Kal iv 
tols ipL7TpOG Blots ovk k'xovGLv aGTpdyaXov ra k'xovra 
aGTpdyaXov, dAA' iv rots oiTLGdev, oti Bel iXacppa 
etvai ra rjyovfieva Kal evKafiTrra, to §' aGcpaXes Kal 
ttjv raGiv iv tols oTuoOev. en Be irpos to dfivve- 

20 G0ai ifjifipiOeGTepav iroiel ttjv TrXrjyrjv tcl oe TOiavTa 


Td Se SlxyXa exei aGTpdyaXov [KovcjiOTepa yap 
tcl oTTLGOev), Kal Sid to e^eiv aGTpdyaXov Kal ov 
pidjvvxd iGTLV, CVS TO iK.Xei7TOV oGTwSes eK TOV 

1 Kal Std SUZ Ogle : Sta vulg. 

a The word used in the Greek is " part." See Introd. p. 28. 
6 See Introduction, pp. 38-39. 



which provide another example of Nature's habit of 
using an organ for secondary purposes, for she 
employs the tail not only as a guard and covering for 
the fundament but also in other serviceable ways. 

There are differences too in the feet of quadrupeds. Hoofs, etc 
Some have a solid hoof, some a cloven hoof ; others 
have a foot that is divided into several parts. Solid 
hoofs are present in those animals which are large 
and contain much earthy substance,* 1 which instead of 
making horns and teeth forms an abscession & so as 
to produce nail, and owing to the abundance of it, it 
produces not several separate nails but a single one, 
in other words, a hoof. Because of this, these 
animals in general have no hucklebone ; and also 
because the presence of a hucklebone makes it 
rather difficult to bend the hind leg freely, since a 
limb that has one angle can be bent to and fro more 
quickly than one that has several. It is a sort of 
connecting-rod, and therefore practically interpolates 
another bit of a limb between the two, thereby in- 
creasing the weight ; but it makes the animal's footing 
more reliable. This explains why, when hucklebones 
are present, they are present in the hind limbs 
only, never in the front : the front limbs have to be 
light and flexible because they go first, while the 
hind limbs must be reliable and able to stretch. 
Further, a hucklebone puts more force into a blow — a 
useful point in self-defence— and animals which have 
one use their hind limbs in this way : if anything 
hurts them they kick out at it. 

Cloven-hoofed animals have a hucklebone, as their 
hind limbs are on the light side ; and that is the very 
reason why they are cloven-hoofed : the bony sub- 
stance stays in the joint and therefore is deficient in 



690 a 

77080? iv rfj /cajui/ret fiivov. ra Se TToXvSaKrvXa 
25 ovk e^et aarpdyaXov ov yap dv r\v TroXvoaKTvXa, 
dAAa togovtov eo^t£eTO to ttX&tos ogov eVe^et 
6 darpdyaXos. Sto /cat twv i^ovrwv avTov rd 
irXelw olx^Xa. 

e O §' dvBpwnos TTooas fieylarovg e^et twv ^wwv 
d)S Kara pieyeOog, evXoyws' fjiovov yap €gtt]K€v 
opdov, wore tovs fieXXovras Su' b'vras e£eiv irav to 
30 tov GwfiaTog fidpog Set firjKos e^etv Ka ^ 1 TrXdros. 
Kal to twv oaKTvXwv orj fieyeOos evavTiws e^et em 
re twv ttoowv Kal twv x ei p£> v /caret. Xoyov twv 
(jL€V yap to Xafifidveiv epyov /cat ttU^zlv, wgt€ Set 
eoo b [xaKpovg <Lyjziv (tw yap KafXTTTOfiivw fiepei irepi- 
Xafipdvet rj X e ^P)> ™ v ^ T ° ^e^/cevat do<f>aXw$, 
Trpos Se 1 tovto Set to fioptov etvat fiet^ov 2 to 
aax L<7T0V r °v ttoSos twv oaKTvXwv. ecr^t'o^at Se 
fieXTiov rj dox^Tov elvai to cgx^tov drrav yap dv 
5 avfJLTraOes rjv evog [loplov TrovrjGavTos , e'cr^tojLteVoj 3 
8' ets" Sa/CTtjAous" tovt ov GVfifiaivei opLotwg. eVt 
Se /cat fipaxets ovt€S tjttov {av) /3AdVT0tvT0. 4 Sto 
TToAucr^tSets" ot TrdSes" twv dvOpwjrwv, ov fiaKpo- 
Sa/CTfAot S* eiGiv. to Se twv ovvx^ov yevog Sta 
tt]v avTTjv aWlav /cat eVt tcov x ei P wv ^X 0V(Jtv ' ^ 
10 yap o/ceVeoflat to, dhcpwrfpia fidXiGTa Sta ttjv 

Tlepl fiev ovv twv ivaljj.wv £wwv /cat ^wotokwv 
/cat ire^wv eiprjTai o^eSoV 7rept irdvTwv* XL twv 
S' ivaifjiwv t,wwv wotokwv Se Ta fiev e'oTt TCTpd- 

1 77pO? 0€ Ogle I 0)(JT€ vulg. 

2 fitllov Piatt, Th. : vo^jll^lv vulg. 
8 iaxtcrfjieva) Peck : -ov PY : -tov viilg. : -ov Ogle. 
* <ai>> Piatt, Th. : ^Xoltttolvto Y : avfi^XaTTToiVTo vulg. 


the foot. The polydactylous animals have no huckle- 
bone, otherwise they would not be polydactylous, 
and the divisions of the foot would cover only so 
much width as the hucklebone itself. So most of 
the animals which have a hucklebone are cloven- 

Man of all the animals has the largest feet for his 
size, and reasonably so, since he is the only one of 
them that stands upright, and as the feet have to bear 
the whole weight of the body and there are only 
two of them, they must be both long and broad. 
Also the toes are short compared with the fingers, 
and this too is reasonable. The business of the hands 
is to take hold and to keep hold of things, and this is 
done by means of that part of the hands which bends ; 
therefore the fingers must be long. The business of 
the feet is to get a firm and reliable footing ; and to 
secure this the undivided part of the foot must be 
greater than the toes. And it is better to have the 
tip of the foot divided than not, for otherwise, if one 
part were affected the whole foot would suffer as well, 
whereas this is to some degree avoided by the divi- 
sion of the tip of the foot into toes. Again, short 
toes are less liable to injury than long ones would be. 
All this indicates why the human foot has toes and 
why they are short. There are nails on the toes for 
the same reason that there are nails on the fingers : 
the extremities have but little strength and there- 
fore specially need to be protected. 

We have now dealt with practically all the blooded 
animals that are viviparous and live on the land, 

XI. We now pass on to another class of blooded (>o Ovipara : 
animals, the oviparous, some of which have four feet, an d Serpents 

QQi quadrupeds. 


690 b , 

7708a ra S' aVoSa. tolovtov 8' iv fiovov yivos 
15 iorlv arrow, to tcov ocjiecov r) 8' air la rrjs arrohlas 
auTaV elprfrai iv tols rrtpl rrjs rropelas tcov £cocov 
SiwpiGfidvoiS' ra 8' aAAa rraparrXrjolav ex ei T V V 


v E^et Se ra £aia ravra Ke<f>aXr)v fikv Kal to, ev 
avrij fiopta hid rds avrds alrlas tols aXXois tols 

20 ivalfiois £cools, Kal yXcorrav iv tco arofiarL rrXrjv 
rod Tforafilov KpoKooelXov ovros 8' ovk av oo^eiev 
€X €iV > dXXd rr)v x<i)pav fiovov. alriov 8* on rporrov 
fiiv riva dfia ^epaatos 1 Kal ivvopos iortv olcl fikv 
ovv to ^epoatos 1 tlvai e^ei y^wpav yXcorrrfs, 8ta Se 
to evvSpos dyXcorros. ol yap IxOves, KaOdrrep eiprj- 

25 rat rrporepov, ol fikv ov ookovolv ^X etv > a ^ v (J< P°~ 
Spa dvaKXlvrj tls, oi 8 s doiapdpojrov e^ouotv. aLriov 
8' oti SXlyrj tovtols XP et ' a2 r V s yXcorrrjs Sta to fir) 
ivhex^crOai fiaoaoBai firjoe rrpoyeveoOai, aAA' iv rfj 
Kararroaet ylveaOai rrjv atodrjcnv Kal rr)v rjSovrjv 
rrdai rovrois rrjs rpo<f>rj$. r) fikv yap yXwrra rcov 

80 x v f JLCOV TTOteT rr)v aicrOrjoLv, tcov ok ioeorcov ev rfj 
Kadooco r) r)oovr]' Karamvofiivwv yap aladdvovrat 
rcov Xirrapcov Kal depficov Kal rcov aAAaw tcov 


tj)v aloOrjGLV (Kal ax^oov rcov rrXelorcov oifjcov Kal 

691 a ioeorcov iv rfj Kararrooet Tjj rdoei rod olao(j>dyov 

yiv€Tai r) ^apts" Sto oi>x ol avrol nzpl rd rrofiara 
Kal tovs x v f lov ^ dKparels elut Kal rd oipa Kal ttjv 

1 WOTOKOLS PUYiy : £u)OTOKOl$ Vulg. 

2 Jjv rovrois XP € ^ a S : XP € ^ a tovtoi? vulg. : delevi. 

° At Be inc. an. 708 a 9 ff ; see also infra, 696 a 10. 
6 At 660 b 13-25. 


and some no feet at all. Actually there is only one 
group that has no feet, the Serpents ; and the reason 
why they have none has been stated in my treatise on 
the Locomotion of A?dmals. a In other respects their 
conformation is similar to that of the oviparous 

These animals have a head, and the parts that com- 
pose it, for the same reasons that other blooded 
creatures have one, and they have a tongue inside the 
mouth — all except the river crocodile, which appar- 
ently has none, but only a space for it ; and the reason 
is that in a way he is both a land-animal and a water- 
animal. In virtue of being a land-animal, he has a 
space for a tongue ; as a water-animal, he is tongue- 
less. This agrees with our previous statement,** that 
some fishes appear to have no tongue unless you pull 
the mouth very well open, others have one which is 
not distinctly articulated. The reason for this is that 
these creatures have not much need for a tongue 
because they cannot chew their food or even taste 
it before they eat it : they can perceive the pleasant- 
ness of it only while they are swallowing it. This 
is because the perception of juices is effected by the 
tongue ; whereas the pleasantness of solid food is 
perceived while it is passing down the gullet, and 
thus oily food and hot food and the like are per- 
ceived while they are being swallowed. Of course 
the Vivipara as well as these creatures have this 
power of perception (indeed, the enjoyment derived 
from practically all edible dainties takes place while 
they are being swallowed and is due to the distension 
of the oesophagus — which is why intemperate ap- 
petite for edible dainties is not found in the same 
animals as intemperate appetite for drink and juices) ; 



iha&rjv), dXXd toT? fiev dXXoig £a>ot? Kal rj Kara 
5 rrjv yevoiv vrrdpx^ alodr]ois 3 eKelvois 8' dvev 
ravrrjs pLovrj 1 rj irepa. rcbv he rerpanohcov koll 
choroKcov ol aavpotj coarrep Kal ol 2 ocpeis, hiKpoav 
exovcri tt]v yXcbrrav Kal err* CLKpov rpixcohrj rrdjj.rrav, 
KaOdrrep etprjrai rrporepov. exovoi he Kal at (^wKat 
hiKpoav rrjv yXcbrrav hio Kal Ar^m 3 rrdvra ra £tod 
eon ravra. 

10 "Eari he Kal Kap^apohovra rd rerpdrroha rcbv 

cboTOKCQV, d)U7T€p OL Ix^VeS . Ta 8' aioOrjrrjpia 

rrdvra ojiolcos exovoi T0 ^ dXXoig t^coois, otov rrjs 
6<j<j)pr]o ecus fJLVKrrjpas Kal oifjews ocpOaX^iovg Kal 
aKorjs cZra, rrXrjv ovk erraveorrjKoray KaOdrrep ot)8* 
ol opvides, dXXd rov iropov fiovov alriov 8* d[i<j)0~ 

15 repois rj rod hepfiaros OKXrjporrjs' ra fiev yap 
rrrepcora avrcbv eon, ravra he rrdvra cboXihcord, 
can 8' r) <f>oXl$ ofioiov X^PQ Aem'So?, <j>voei he 
GKXi)p6repov. SrjXol 8' irrl rcbv ^eAa>i'a>v rovro 
Kal irrl rcbv fieydXcov d(f>ecov Kal rcbv rrorafilcov 
KpoKooeiXcov LGXvporepat yap yivovrai rcbv oorcbv 
cos ovoai roiavrai rrjv <f>vaiv. 

20 Ovk exovoi he ra t>cba ravra rrjv dvco fiXecfcapiha, 
coorrep ovh* ol opviOes, dXXd rfj Karco [ivovoi oca 
tt)v alrlav rrjv eipijfievrjv eV iKelvcov. rcbv fxev ovv 
opvldcov evioi Kal OKapoafivrrovGiv vpievi Ik rcbv 
KavOtbVj ravra he ra t,cba ov oi<aphafxvrrei' OKXy]p~ 

25 ochOaXfiorepa yap ion rcbv opvtOwv. alriov 8' on 
€K€ivois XPV Gi H' COT ^P a V o^vcorfla 4, Trrrjvois ovoi rrpos 

1 5' aivtv Taih-qs fioi'T} Peck: 5' av ?J coairep fiovr] Y: S* 
a)(77Tepavd vulg. ; plurima hie transposuit Ogle, 

2 Kal ol Y : ol vulg. 



but whereas the rest of the animals have the power of 
perception by taste as well, these are without it 
and possess the other one only. Among oviparous 
quadrupeds, lizards (and serpents too) have a two- 
forked tongue, the tips of which are as fine as hairs. 
(This has been stated earlier.") Seals also have a 
forked tongue. This forked tongue explains why all 
these animals are so dainty in their food. 

The four-footed Ovipara also have sharp interfitting 
teeth, as Fishes have. Their sense-organs are all 
similar to those of other animals : nostrils for smell, 
eyes for sight, and ears for hearing — though their ears 
do not stand out : they are merely a duct, as in 
birds ; and in both groups the cause is the same, viz. 
the hardness of their integument. Birds are covered 
with feathers, and these creatures are all covered 
with horny scales which correspond in position to the 
scales of fishes, but are harder in substance. This 
is clearly illustrated by the tortoises, the great snakes, 
and the river crocodiles, where the scales are made of 
the same material as the bones and actually grow 
stronger than the bones. 

These animals, like birds, have no upper eyelid ; 
they close their eyes with the lower lid. The reason 
which was given 6 for birds applies to them too. Some 
birds can also blink by means of a membrane which 
comes out of the corner of the eye ; but these 
animals do not do this, since their eyes are harder 
than birds' eyes. The reason for this is that keen 
sight is of considerable use to birds in their daily 

• At 660 b 9. 6 At 657 b 6 ff. 

3 At'xva Karsch : ur^vd vulg. 
4 6£va)7rla teal to iroppco 7rpotBeiv UY. 




tov filov, tovtols §' tjttov* TpcoyXoBvTa yap TTOLVTOL 


Ets" Bvo Be Btrjprjpievrjs rrjs Ke(f>aXrj$> tov t€ avco 
piopLOV /cat ttjs oiayovos Trjs koltqj, av6pco7TO$ p.ev 1 


so klvovgl Tas otayovas Kal els to TrXdytov, ol 8' 
l^Oves Kal opvtOes Kal to, (Lotoko. tlov TeTpaTroBwv 
els to avco Kal koltoj povov. aiTiov §' otl r) fiev 
691 b Toiain-77 KLviqoLs xpTjat/xos" €t ' ? T ° oaK ^ v Kai BieXeiv, 
r) S' els to vrXdyiov €7U to Xealveiv. tols ptv ovv 
€){ovol yofJL<f>LOVs xprjoipos; rj els to rrXdytov KLvrjats, 
tols Be pi) eypvoiv ovBev xp7]otpos, Bioirep dcfrfiprjTat, 
iravTuiv twv tolovtwv ovBev yap rroiet irepiepyov r\ 
6 (j>voL$. tcl pev ovv aAAa TrdvTa Kivet ttjv otayova 
TTjv KaTW t 6 Be TTOTapios KpoKoBeiXos piovos ttjv avco. 
tovtov S' a it tov OTi 7Tp6s to Xafietv Kal KaTaoyexv 
dxprjcrTovs e%ei tovs TroBas' piKpol yap elot Trdparav. 
7rpos ovv TavTas tols xP e ^ a? dvTi ttoBlov to OTopta 
r) <f>vcns xp^cn/xov avTco eTrotrjoev '. -npbs Be TO 

io KaTaax^iv r) XafieTv, oiroTepooQev dv rj r) 7rXrjyr) 
laxvpoTepa t TavTTj xP r } (JL l JiCOT ^P a xwovpevrj Igtlv* 
r) Be 7rXrjyr) laxvpoTepa del dvcoQev rj KaTCoOev en el 
ovv dpLcfroTepcov ptev Bid tov uTopaTos r) XPV UL S> 
tov Xafietv Kal tov BaKelv, dvayKatOTepa 8' r\ tov 

is KaTaax^lv p.r\Te ^tpa? ex 0VTl / X7 ? T€ TroBas ev(f>veis, 
Xpf]Gipd}Tepov Tr)v dva)9ev Ktveiv utayova rj ttjv 
KaTCoOev avTols. Bid to avTo Be Kal ol KapKivot 
to dvcoBev TTjs XV^ys klvovol ptoptov, dAA' ov to 
KaTwBev dvTi ^etpos" yap e'xovut ret? X7jAdV, waTe 
Trpos to Xafielv dXX ov TTpos to SteXetv ^p^at^ov 
1 fxh ovv vulg. : fikv YZ. 



life, because they fly about ; but it would be very 
little good to these creatures, because they all spend 
their time in holes and corners. 

Their head has two divisions : the upper part, and 
the lower jaw. In man and in the viviparous 
quadrupeds the lower jaw moves from side to side as 
well as up and down ; in fishes, however, and birds 
and these oviparous quadrupeds it moves up and 
down only. The reason is that this vertical motion is 
useful for biting and cutting up food, while the 
sideways motion is useful for grinding the food down. 
Of course this sideways motion is useful to animals 
which possess grinder-teeth ; but it is of no use to 
those which lack grinders, and so not one of them 
has it. Nature never makes or does anything that is 
superfluous. All these animals, then, move the lower 
jaw — with one exception, the river crocodile, which 
moves the upper jaw, and the reason for this is that 
his feet are no use for seizing and holding things : 
they are too small altogether. So Nature has given 
him a mouth which he can use for these purposes 
instead of his feet. And when it comes to seizing 
things and holding them, the most useful direction 
for a blow to take is that which gives it the greatest 
strength. Now a blow from above is always stronger 
than one from below. And to an animal who has no 
hands and no proper feet, who has to use his mouth 
for seizing his food as well as for biting it, the power 
to seize it is the more necessary ; and therefore it is 
more useful to him to be able to move his upper jaw 
than his lower one. For the same reason crabs move 
the upper part of their claws and not the lower : 
claws are their substitute for hands, so the claws have 
to be useful for seizing things (not for cutting them 



691 b ^ ^ 

20 Set etvat rrjv -xj]\rjv to he hieXeiv Kal haKetv ohov- 
rcov epyov eortV. rot? \xkv ovv KapKivois Kal rot? 
aAAots* ocfols evhex^Tat a^oXalcos iroielodai tt)V 
Xfji/jiv Sta to fir) iv vypco elvai r-qv xprjcriv rod 
GTOfiaroSy Sirjprjrai, Kal XafipdvovGL jiev \epalv rj 
TToaly Statpouat he ra) arojJLari Kal oaKvovuiv to2$ 

25 0€ KpOKOOetXoiS €77* d[A(f>OTepa xP?l (Jl l JLOV T ° (JTOfia 
7T€7rotrjK€v rj (f>v<Jis, KLvovfidvojv ovtco twv OlOyOVWV . 

"E^ouat he Kal avx^va rrdvTa ra rotavra Sta to 
TrXev/jiova k'xeiv oiyovrai yap to Trvevfta Sta Trjs 
dpTTjp [as jxrjKos e^ouaT^. 

1, E77€t ok TO fJL€Ta£v K€(j>aXi]S Kal W\XWV K€KXrjTai 

avyr\v y r\KiOTa twv tolovtwv 6 o<f>is ho^etev dv 
30 €\€lv av\€vay aXXa to dvdXoyov tw au^eVt, et ye 

Set TOt? €Lp7]fJL€VOL9 eO^aTOtS' BtOpt^€LV TO fXOpLOV 

tovto. thcov oe irpos T(i ovyyevrj twv ^wwv 

692 a imdpxei tols o<f>eoi to GTpe<j>eiv ttjv Ke<f>aXr)v el? 


S' oVt Kaddirep to, evTOfxa £Xlktov icrTiv> ware 
evKafiTTTovs ^X €LV Ka * L X 0V ^P c ^ ei? T °us* ctttovSvXovs . 
i£ dvdyKrjs fikv ovv Sta TavTrjv ttjv air lav tovto 

5 oviif$efir)Kev avTols> tov hk fieXTiovos eveKev rrpos 
(f>vXaKT)v twv oTuaOev fiXaTTTovTwv fiaKpov yap ov 
Kal arrow d<f>ves eoTi rrpos Te ttjv GTpo^rjv Kal TTpos 
ty]v twv OTTicrOev Trjprjcnv' ovhkv yap ocfreXos atpeiv 
fieVy GTpe<f>eiv oe fir] hvvaaOat ttjv Ke<f>aXr}v. e'xovai 
he Ta TOtauTa /cat tw OTr\Bei dvdXoyov fjioptov. 

io fiaOTOVs S' ovk exovGiv out' evTavOa ovt' iv tw 
dXXw awfiaTL, 6/jloIws S* ouS' 6pvis s ouS' lx@vs 
ovhels. a'lTiov he to firjhk ydXa e^etv tovtwv 

1 hinc usque ad 695 a 22 varia codd. ; text. vulg. exhibui. 


up : this, and biting, is the business of the teeth). 
In crabs, then, and in other creatures which, because 
their mouth does not come into action while under 
water, can take their time about seizing their food, 
the labour is divided : they seize their food with 
their hands or feet, and cut it up and bite it with 
the mouth. For the crocodile, however, by making 
the jaws move as I have described, Nature has 
constructed a mouth which can be used for both 
these purposes. 

All these animals have also a neck ; this is because 
they have a lung and there is a long windpipe through 
which they admit the breath to it. 

Since the neck is the name given to the part of 
the body between the head and the shoulders, the 
serpent would appear to be the very last of these 
creatures to possess one : at any rate, if the neck is 
to be denned by the limits mentioned above, he has 
merely something analogous to a neck. Compared 
with kindred animals, serpents have this peculiarity : 
they can turn their heads backwards while the rest of 
the body remains still. The reason is that their body 
(like an insect's) can roll up ; the vertebrae are cartila- 
ginous and flexible. This, then, is the necessary cause 
why they have this ability; but it serves a good purpose 
too, for it enables them to guard against attacks from 
the rear, and with their long bodies devoid of feet 
they are ill adapted for turning themselves round to 
keep watch over the rear. To be able to raise the 
head and yet unable to turn it round would be useless. 
These animals have also a part which is a counter- 
part to the breast. But they have no mammae either 
here or elsewhere ; nor have any of the birds or fishes. 
This is because the mammae are receptacles, vessels, 



692 a 

p.r)9iv 6 Bk fiCLGTOs VTroBox?) Kdl coo-rrep dyyetov 
ion ydXcLKTOs . ydXa 5' ovk eya ovre ravra our' 
dXXo ovBkv rail' ftr) tcporoKovvrcov iv avro'is, Blotl 
cootokovolv, iv Bk rep coco rj rpoSi] iyylverat iv 
ro7$ CcporoKois ya\a.KTcoor]5 vrrdpxovoa. aatfii- 
15 orepov Bk rrepl avrcov XexOi]aeraL ev tols rrept 
yevioecos. rrept Bk rrjs rcov oKeXcov 1 Kdf.iifj€cos iv 
tols rrepl rropelas rrporepov irrioKerrraL koli'tj rrepl 

"E^Ot'CK ok Kdl K€pKOV 7Ct TOLOLVTa, TCL flkv f-LClCcO 

ra 3' iXdrrco, vrrkp ov rrji' alrlav KaOoXov rrporepov 

20 'Icr^T'oraros" S' 6 x a l- iaL ^cov rcov lootoklov Kal 
rreCcbv iortv oXiyaL^orarov yap ion rrdvrcov. ravro 
S' atriov rov rfjs faxV^ V^ 01 ^ T °v tcpov z rroXv- 
fiopSov yap ylverac Bid rov chofiov, 6 ok tf>6fios 
Kardijjv£is St' oXtyaL^or^rd ion Kal evBeiav depfio- 


692 b Hepl p.kv ovv rcov ivalficov Ccocov rcov re drroBcov 
Kal rerparroBcov, oaa fiopta ra ck-os e\'et Kal Bid 
rivas alrias, etprjrat a\'e3dr. 

XII. 'Ev Bk tols opviotv 7] ~p6$ dXXrjXa Btacfiopd 
iv rrj rcov ^Lopicov iarlv vrrepoxfj Kal iXXelipet Kal 
5 Kara to p.aXXov Kal fjrrov. elal yap avrcov ol p.kv 
f.LaKpoGKeXeis ol Bk fipaxvoKeXeLSj Kal rrjv yXcbrrav 
ol ^kv rrXarelav exovaiv °' L Bk orevip" opLoicos Bk 
Kal irrl rcov dXXcov f-ioplcov. IBla Bk fj.6pia dXlya 

1 OK€\cov PZ, Ogle : Kdfi-rvXwv ok€\o>v V : KdfnrvXcuv vulg. 

3 repi Be . . . -di-rcov fortasse secludenda. 

s correxit Peck. cf. 667 a 1 1 seqq. : tovtov 5' a'nov to fjOo; 
rov Lcpov to Trj$ ih'xrjs vulg. : airtov Be to rijs i/a-^? fjOos icrrtv 
avrov PSUZ : sed fortasse haec verba secludenda. 


as it were, for the milk, and none of these creatures 
has any milk. Neither has any of the other animals 
that are not internally viviparous ; the reason is that 
as they produce eggs the milky nutriment which they 
contain goes into these eggs. A more detailed 
aecount of these matters will be given in the treatise 
on Generation. 0, With regard to the way in which they 
bend their legs, a general account, including all 
animals, has already been given in the treatise on 
the Locomotion of Animals? 

These creatures have a tail, some a large one, some 
a small one. We have already given the reason for 
this as generally applicable. 

Among the oviparous land-animals, the chameleon 
has the least flesh on him ; this is because he has 
least blood, and the same reason is at the root of the 
animal's habit of soul — he is subjeet to fear (to which 
his many changes in appearance are due), and fear is 
a process of cooling produced through scantiness of 
blood and insufficiency of heat. d 

This fairly concludes our account of the external 
parts of the blooded animals both footless and four- 
footed, and of the reasons thereof. 

XII. We now pass on to Birds. As among them- (ii.) Birds, 
selves, they differ in their parts in respect of the 
more and less, and excess and defect e — e.g., some of 
them have long legs, some short ones ; some have 
a broad tongue, some a narrow one ; and similarly 
with the other parts. Thus, as among themselves 

a At 752 b 16 ff. 

b At 712 a 1 ff. See also below, 693 b 3, and additional 
note on that passage, p. 433. 
c At 689 b 1 ff. 

d Compare the passages at 650 b 27 and 667 a 11 ff. 
e See 644 a 19, and introductory note on p. 19. 



692 b 

oia<f>epovTa exovacv dXXrjXwv irpos Be tol aAAa £aia 

Kal Tjj fJLOp<f>fj TWV fJLOpLWV Oia<j>epOVGlV . 7TT€pOJTOl 

10 pL€V ovv aTjarres elaiv, Kal tout' lSlov k'xovai twv 
aXXwv. tol yap iiopia twv l^wwv tol yckv rpt^cora 
€GTi tol hk (^oXlowtol tol Be AeTrtSajTa, ol 8* opviOes 

TWV 0€ GX L(TT ° V €°"T L > K0LL T0 ft-kv OLKavXoVy TO 8' 

15 k'xei KavXov. k'xovai Be Kal iv Trj KecfraXfj nepLTTr^v 
Kal toiov T7]v tov pvyxovs (f)vaiv 7Tp6s TaAAa* tols 
fjikv yap iXe(f>aGLV 6 llvkttjp olvtI x €L P ( ^ >v > twv S 

eVTOfJLWV €1 'LOIS T) yXoJTTa OLVtI GTOfJiaTOS, tovtols 

§' olvtI oBovtwv Kal ^etAcov to pvyxos ogtlvov ov. 1 
Trepl Be twv alGOrjT-qplojv e'lprjTai irpoTCpov. 
20 Avx^va B e^et rerafxevov Tjj (f>vaei } Kal Bia ttjv 
avTvjv air lav rjvrrep Kal TaAAa* Kal tovtov to, fikv 
fipaxvv tol Bk fiaKpov, Kal ax^Bov olkoXovOov tols 
GKeXeai tol TrXelaTa. tol Kiev yap LiaKpoaKeXrj 
LiaKpov tol Bk fipaxvGKeXrj fipaxvv e^et tov avx^va } 
X^jpls twv GTeyavoTTGOwv tol itkv yap el ef^e fipa- 

693 a x vv GKeXeGL LiaKpois, ovk av vTrrfpeTei avTols 6 

avx'rjv 7rp6$ TTjv oltto Trjs yrjs voLirjv, tols S' el 
LiaKpos T\v eVt fipaxeGiv. €tl he 2 tols Kpew<f>dyois 
avTwv vnevavTiov av rjv 5 to [JLrjKos Trpos tov fSlov 
5 6 yap fiaKpos avx^v oLGOevrjs, tols S' 6 /3los £k 
tov KpaTetv €Gtlv. BLoirep ovBkv twv yapLtftwvvxwv 
fiaKpov exei tov avx^va. tol ok GTeyavoiroBa Kal 
{rd) 4 OLTjp7]Liei'ovs Likv k'xovTa tovs iroBas gzgiliw- 


1 6v Y, Ogle : om. vulg. 


they have few parts which differ from one to another. 
But as compared with other animals, they differ in 
respect of the form of their parts. One peculiarity 
of the birds is that they all have feathers, whereas 
in other animals the parts are covered with hair, or 
scales, or horny plates. A bird's feather is split, and 
therefore different in form from the wing of certain 
insects, which is undivided ; as well as having a shaft, 
whereas the insects have none. Another peculiarity 
of birds is the beak, an extraordinary appendage to 
the head. It is made of bone, and serves them 
instead of teeth and lips, just as the elephant's trunk 
takes the place of hands, and the tongue of certain 
insects replaces a mouth. We have spoken already 
of the sense-organs. a 

Birds have a neck which sticks up, and for the same 
reason that other creatures have one. Some have a 
long neck, some a short one : in most of them it corre- 
sponds in length fairly closely to the legs, so that the 
long-legged birds have a long neck and the short- 
legged birds a short neck (web-footed birds excepted.) 
What assistance in getting food out of the ground 
would a short neck be to a bird on long legs, or a long 
neck to a bird on short legs ? Furthermore, the 
carnivorous birds would find a long neck a real dis- 
advantage in their daily life. These birds depend 
for their livelihood on superior strength, and length 
of neck means lack of strength ; so no crook-taloned 
bird has a long neck. Web-footed birds, how- 
ever, together with others in the same class whose 
a In Book II. chh. 12 ff. 

2 Se Langkavel : ye Yb : om. vulg. 
3 av rjv PY6, Ogle : om, vulg. 
4 <ra> Ogle. 



693 a 

jievovs Be Kal 1 ev toj avrtu yevei ovra rots' areyavo- 
ttogl, tov fiev au^eVa fxai<p6v exovaiv (xptfaifjios 
yap toiovtos o>v rrpos ttjv Tpo<f>rjV tt^v €K tov 

10 vypov), rd he oKeXrj upos tvjv vevaiv jSpa^ea. 

Aia(f)opav S' k'xei Kal tol pvyx 7 ] Kara rovs fiiovs. 
rd fiev yap evOv k'x^i tol he yapupov, evOv puev oca 
rpo(f)7]s eveKev, yapufcov he ra d)fjLO(f)dya' yjp-qoipsov 
yap TTpos to Kpareiv to tolovtov, ttjv he Tpocfrrjv 
dvayKaiov arro ^ojojv rtopl^euOaiy Kal rd ttoXXcl 

is pLa^oixevoLs. ocrtov 8' eXeios 6 filos Kal Troo<f>dyos, 
TrXaTi) to pvyxos exovoiv irpos t€ yap ttjv opv^iv 
Xprjo-ipLov to toiovtov Kal 77po? rrjv ttJ? Tpo<j)rjs 
GTTOLcnv Kal Kovpdv. evta Be Kal [laKpov eyei to 
pvyxos tojv toiovtojv, u)G7rep Kal tov avyeva, Bid 
to Xafifidveiv ttjv Tpo<j>r}v 4k tov fidOovs. Kal rd 
7ToXXd tojv toiovtojv Kal tojv GTeyavoTToBcov Tj 

20 d^Aa)? rj /card 2 fiopiov 2 OrjpevovTa tfj tojv ev to> 
vypco evia ^cphapiojv Kal yiveTai to!? toiovtoi? 6 
fiev ai)^y KaOduep dXieVTats d 4 KaXapios, to Be 
pvyxos olov rf opfjud Kal to ayKiOTpov. 

Td he Trpavrj tov GojjiaTOS Kal ra uVna, Kal rd 
tov KaXovfievov OojpaKos errl tojv t€t paTrohojv s 

25 6Xo(j)Vr}S 6 TOTTOS €776 TO)V OpvCBojV eOTIV' Kal €^OUO"tV 

a777]pT7]/x€Vas > dvTl tojv ppaxidvwv Kal tojv UKeXojv 

693 b TOJV TTpOoQiOJV* rd? 7TT€pVyaS, ihtOV TL [JLOpLOV, 

hiorrep dvTl ojpLOTrXdTrjs rd TeXeVTala eirl tov vojtov 
tojv TTTepvycov e'xovcriv. 

HKeXrj he KaOdrrep dv9po)7TO$ Bvo, /ce/ca/x/xeVa 

1 Kal Yb, Ogle : ws vulg. 

2 Kara. Y, Ogle : Kara to vulg. 

3 post fiopiov habet raiiro vulg. : ravra S : ravra P : tovtois 
com. Ogle. 



feet though divided into toes yet are fashioned like 
a snub-nose — these have long necks, because a long 
neck is useful to them for getting food out of the 
water. Their feet, on the contrary, are short so that 
they can swim. 

Birds' beaks also differ according to their different 
habits of life. Some beaks are straight, some curved ; 
straight if they are used simply for feeding, curved if 
the bird eats raw meat, because a curved beak is 
useful for overpowering their prey, and such birds 
have to get their food from animals, most often by 
force. Those whose life is spent in swamps and are 
herbivorous have broad beaks, which are useful for 
digging and pulling up their food and for cropping 
plants. Some of them, however, have a long beak and 
a long neck as well, because they get their food from 
some depth. Practically all these birds and the com- 
pletely or partially web-footed ones live by preying 
upon certain of the tiny water-animals, and their 
neck is to these birds what his fishing-rod is to an 
angler, while their beak is like a line and hook. 

The under and the upper sides of the body (i.e. of 
what is called the trunk in quadrupeds) are in birds 
one uninterrupted whole. Instead of arms and fore- 
legs they have wings attached to this part (wings are 
another peculiarity), and hence, instead of having the 
shoulder-blade on their back they have the ends of 
the wings there. 

Birds, like men, have two legs, which are bent in- 

° According to Ogle, this means that the main stem of the 
toe corresponds to the ridge of the nose, and the lobes on 
either side of it to the flattened nostrils. 

* aXtevTcus 6 PQSU : clXlcvtikos 6 Yb : aXitvTLKOS vulg. 
6 rj Yb : om. vulg. 

6 sic Y6, Ogle : dmjpT. yap dim et mox ex ov<Jt P os t -npoadlcov 



693 b 

Kada.7Tep ra rerpaTroSa eiGWy /cat oi>x worrep dvdpw- 
5 770? e£w Ta? Be TTTtpvyas, d>$ ra irpoodia crKeXrj 
twv rerpaTTohojVy Ittl to 7repL<f)epes. BLttovv 8' 
dvdy«r)$ euTiv twv yap evalpiwv rj tov opvtOos 
ovoidy dfia Be /cat TTTepvywros , rd 8' evoufia ov 
KLvetrat TrXelooLV r) rerrapuL orjfieLOLg, rd fiev ovv 
d7TT]pTr\\ieva fiopia rerrapay wo7rep Tot? dXXois 
rot? 77€^ots* /cat rots* TropevriKois , eWt /cat rots" 

10 opviatv dXXa Tot? fiev /3pa)(toves /cat GKeAr), rot? Be 
TerpdirooO- UKeXrj rerrapa VTrdp^ety Tots* 8' dpviuiv 
dvTi twv TTpouOiwv GKeXwv Tf fipaxtdvwv 7TTepvye<s 
to "Blov €<jtlv Kara rauras* yap tovikoi" etcrt, tw 
8' opviOi ev rfj ovala to tttt\tik6v iartv. WGTe 
XeiTrerai auTots* e£ dvdyKrjs Blttoglv elvai % ovtw yap 

15 rerrapGL O7)p<elois KLvrjcrovrai fierd twv 7Trepvywv. 
HrfjOos 8' e^ovGiv diravres 6£v /cat orapKwBes } 
6£v puev irpos TTjv TTTTjUiv (rd yap TiXaTea ttoXvv 
depa cLOovvra BvoKLvrjrd eari), uap«w8e$ Be, Blotl 
to 6£v da 9 eve? {irj ttoXXt^v ^X ov OKeTT-qv. 

'Ytto Be to arrjOos KoiXla Jiexpi trpos tt)v e^oBov 

20 rod TTepLTTCQ/JLaros /cat ti]V twv uKeXwv KapL7Tr\Vy 
KaOdirep rots* Terpdiroui /cat rots* avSpwirois . pie- 
rafj) {lev ovv twv TTTepvywv /cat twv OKeXwv rayra 
ra p.opid euTiv. 

'QpL<f)aX6v 8' ev pcev Tjj yeveoei aVavTa e^et 

1 sic PY6, Ogle : oKeXrj, rot? Se rerp. om. vulg. 

2 7ttt}tlkoC conieci ; idem Th. {volatiles Gaza). 

° For an explanation of Aristotle's terminology on this 
subject see additional note on p. 433. 

b The chief difficulty in translating this passage is due to 
the word tovlkol, a jargon-adjective in -lkos, which seems to 
have been suggested to Aristotle's mind by the similar adjec- 


wards as in the quadrupeds, not outwards as in man. fl 
The wings are bent with the convex side outwards, 
like the forelegs of quadrupeds. It is inevitable that 
a bird should have two feet, for (a) it belongs essenti- 
ally to the blooded creatures and (6) it is winged, 
and (c) four is the greatest number of motion- 
points which a blooded creature can have. So there 
are four parts (or limbs) attached to a bird's body, 
and this corresponds exactly with the other blooded 
creatures, viz. those that live and move upon the 
ground. The only difference is that whereas the 
latter have two arms and two legs (or, if they are 
quadrupeds, four legs), the peculiarity of birds is 
that they have wings instead of arms (or forelegs). 
As its very essence includes the power to fly, a 
bird must have something which it can stretch out, 
and wings provide this. 5 So it remains that of ne- 
cessity a bird shall have two feet: these with the two 
wings bring up the number of its motion-points 
to four. 

All birds have a sharp-edged, fleshy breast : 
sharp-edged, for flying (a wide surface displaces so 
much air that it impedes its own motion) ; fleshy, 
because a sharp-edged thing is weak unless it has 
a good covering. 

Below the breast is the stomach, which extends (as 
in the quadrupeds and in man) as far as the residual 
vent and the point where the legs join the body. 

Those are the parts, then, which have their situation 
between the wings and the legs. 

Birds, in common with all animals which are pro- 

tive tttt}tik6v in the next line. Literally, the passage reads : 
" for it is at these [viz. the wings] that birds are stretchable ; 
and flight-ability is included in the essence of a bird." 



693 b 

ooairep ^cporoKeirai rj woTOKelrai, tcov S* opvldojv 
av^TjOevrcov aSrjXos. rj 8' curia SrjXrj iv rot? 7T€pl 
25 ylv€ULv els yap rd evrepov rj crvficfrvcris yiverai, Kal 

Ol>X W0~7T€p TOIS ^WOTOKOLS TO)V (^AefScbv Tl fXOpLOV 

"En tojv SpvWcov ol {lev TrrrjrtKol Kal Ta? rrripvyas 

694 a fieydXas ix oV(JL Kal icrxvpds, olov ol yapupwvvx^ 

Kal d)fXO(f)dyoi' dvdyKrj yap ttttitlkovs 1 eivai Sid rov 
fiiov, wu6^ eveKOL rovrov Kal rrXrjOos e^oucri rrreptov 
Kal rds TTrepvyas fteydXas. eon 8' ov \xovov to, 
5 yapj\s(javv\a dXXa Kal dXXa yivrj opviOwv TTTrjTiKa, 
ogols rj crwr^pta iv rfj raxvrrjrL rr^s irrrjaecos 

eKTOTTlGTlKOg 6 jStO?. tVia 8' OV TTTTjTLKa TWV 

opviOwv iarlv dXXa jSapea, oh 6 ftios iiriyzios Kal 
eon Kap7Tocj)dya rj irXwrd Kal rrepl vSwp fitorevov- 
oiv. eon 8e rd fiev rwv ya\v\swv\)xwv uw\xara 
puKpd dvev 2 rwv mepvywv Sid to els ravras* dva- 
XluK€u6ai rrjv rpo<j>rjv (Kaiy* els rd dirXa Kal rrjv 

10 fiorjOeiav Tots* 8c fir) ttt7)tikoZs rovvavrlov rd ow~ 
fxara oyKwhr), hid fiapea iariv. exovai 8' eviot 
rwv fiapiwv porjOeiav dvrl rwv rrrepvywv rd KaXov- 
fxeva b rrXrjKTpa IttI tols aKeXeaiv. dfia 8' ol avrol 
ov yivovrai TrXrjKrpa e^ovres Kal yafiipwvvx^S' 

15 ainov 8' on ovSev rj envois ttoi€l rrepUpyov . eon 
Si rots fjiev yapupwvvx 01 ^ Kal tttt(tikois a^p^ara rd 

1 tttt)tlkov5 P, Rackham : ttttjtlkcl Yb : 7tttjtiko is Z t vulg. 
2 post avev habent tcov 7TTeptov Kal Y6. 
3 els Tavras QSUZ : ivravda vulg. 
4 <t<ai> Ogle. 5 desinit Z. 

° This passage must be supplemented by reference to others 
(such as Be gen. an. 753 b 20 ff., and Hist. An. 561 b), in which 
Aristotle speaks of two umbilici or umbilical cords — i.e. he 
recognized the allantois as well as the umbilical vesicle. He 



duced alive or out of eggs, have an umbilicus while 
they are developing, but when they are more fully 
grown it ceases to be visible. The reason for this is 
clear from what happens during their development : 
the umbilical cord grows on to the intestine and 
unites with it, and does not form a part of the system 
of blood-vessels, as it does in the Vivipara. a 

The good fliers have big strong wings, e.g. the 
birds which have crooked talons and feed on raw 
meat : these must be good fliers owing to their habits 
of life, and so the} 7 have an abundance of feathers and 
big wings. But there are other sorts of birds which are 
good fliers beside these : birds whose safety lies in 
their speed of flight ; and migrants. Some birds are 
poor fliers : heavy birds, which spend their time on 
the ground and feed on fruits ; or birds that live on 
and around the water. The crook-taloned birds, leav- 
ing out of account their wings, have small bodies, be- 
cause the nutriment is used up to produce the wings 
and weapons of offence and defensive armour. The 
poor fliers, on the contrary, have bulky, and therefore 
heavy, bodies. Some of these instead of wings have 
as a means of defence " spurs " on their legs. The 
same bird never possesses both spurs and talons, and 
the reason is that Nature never makes anything that 
is superfluous or needless. Spurs are of no use to a 

states that in the bird's egg, as the embryo grows, the allantois 
(the " second umbilicus ") collapses first and then the " first 
umbilicus" {Be gen. an. 754 a 9). Actually the reverse 
order is the correct one, but the interval is comparatively 
short. The umbilical vesicle in mammals, which shrivels 
very early in the process of development, escaped the notice 
of Aristotle, who supposed their allantois to be comparable to 
the umbilical vesicle of reptiles and birds. The umbilical 
vesicle of mammals was discovered by Needham in 1667. 
(See Ogle's note ad loc.) 


694 a 

irXriKTpa' xp^ipia yap earcv ev reus ire^ats fta^ats, 

8lO VTTOipX^t il'lOLS TCOV f3ap€LOV TOVTOLS 8' OV 

pidvov axpr}OTOi dXXa Kal fiXafiepol ol yapa/jot 6vv)(€S 


20 8to Kal ra yapupcovvxa* rravra cpavXoos iropeverai 
Kal irrl 7T€rpai£ ov Kadi^dvovGLV v7T€vavTta yap 

aVTOLS TTpOS apL<f)6T€pa Tf TCOV 6vV)(LOV <f)VOLS. 

'Ef avdyKYjg he tovto rrepl ttjv yiveoiv ovpLfiefirj- 
Kev. to yap yecohes iv tco awpbari e^oppbcopbC- 
vov 1 XP^ 01 } 10 - P'Opia ylverat rrpos ttjv dXKTjV avco 

pi€V f)V€V pVy^OVS €7TOLrjG€ GKXrjpOTTjTa Tj pLey€0OSj 

25 dv he Karoo pvfj, irXrjKTpa ev tols GKeXeaiv rj €7tI 
tcov rrohcov 6vv)(ojv p.eyeOos Kal ivyyv. dp.a 8' 
aXXoOt Kal dXXoOi e/caara tovtcov ov Troiel' 8ta- 
OTTCopLevrj yap doQevrjs yiverai rj <f>vais tovtov tov 
TTZpiTTOjpLaros. tols he aKeXcov KaTaoK€vat,€i pLr)- 
694 b kos- eviois 8' dvrl tovtcov ovpLTrXrjpoZ to pL€ra£v 
rcov rrohcov ' Kal hid tovto avayKalcog ol ttXcotoI 
tcov opvlOcov ol pikv drrXcos elal GTeyavorrohes , ol Se 
hirjprjpLevrjv piev €){ovoi TTjV Ka9* eKauTa tcov haKTV- 

5 XcOV (f)VOLV y TTpOS eKaOTCp 8' aVTCOV 7TpOG7T€<f)VK€V 

otov TrXaTrj Ka6* oXov aureus. 

'E£ dvdyKrjs p,ev ovv raura ovpL^alvei Sid Tavras 
Tas abr las' cog he 8ta to fieXTiov k'xovai tolovtovs 
tovs rrohas tov filov x&P lv > ° va £o~jvt€S ev vypcp Kal 
tcov TTTepvycov 2 dxpeltov ovtcov tovs rrohas XP 7 ] ^' 


1 i£opfjia)fA€vov Peck : Kal e£op{j.ov €K tovtov to. Y6 : efco pvkv 
Langkavel ; fortasse i^opfxaTat Kal eV tovtov to.. 

2 Trrepvycov Y6, Ogle : vTepwv vulg. 



bird that has talons and can fly well : spurs are useful 
for fights on the ground, and that is why certain of 
the heavy birds possess them, while talons would not 
be merely useless to them but a real disadvantage ° : 
they would stick in the ground and impede the birds 
when walking. And in fact all crook-taloned birds 
do walk badly, and they never perch upon rocks ; 
in both instances the nature of their claws is the 

This state of affairs is the necessary result of the 
process of their development. There is earthy sub- 
stance in the bird's body which courses along and 
issues out and turns into parts that are useful for 
weapons of offence. When it courses upwards it 
produces a good hard beak, or a large one ; if it 
courses downwards it produces spurs on the legs or 
makes the claws on the feet large and strong. But 
it does not produce spurs and large claws simul- 
taneously, for this residual substance would be 
weakened if it were scattered about. Again, some- 
times this substance makes the legs long ; and in 
some birds, instead of that, it fills in the spaces be- 
tween the toes. Thus it is of necessity that water- 
birds either are web-footed, simply, or (if they have 
separate toes) they have a continuous fan or blade, 
as it were, running the whole length of each toe and 
of a piece with it. 

From the reasons just stated it is clear that feet 
of this sort are the result of necessity, it is true ; but 
they conduce to a good end and are meant to assist 
the birds in their daily life, for these birds live in the 
water, and while their wings are useless to them, 
these feet are useful and help them to swim. They 

° See above, note on 648 a 16. 

o 411 


694 b 

10 al Ko>7Tai to?s ttXIovci koli 1 ra TTTtpvyia tois iyftv- 
oiv 816 Kat idv tojv fjcev ra Trrepvyca o<j>aXfj s tojv 
Se to {JL€Ta£v tojv irohojv, ovKeri viovoiv. 

"Eviot Se ixaKpouKeXels tojv opviOoJV elcrlv. avriov 
8' oti 6 fitos tojv tolovtojv e'Aeios** to, §' opyova 
Trpos to epyov rj <f>vcris TToiei, dAA' ov to epyov npos 

15 to, opyava. 8 id piev ovv to per) ttXojtol elvat ov 
OTeyavoTTohd eon, 8 id Se to ev vrreiKoVTi etvai t6v 


ttols e^oucri ttXziovs ev tois SolktvXois ol ttoXXol 

aVTO)V. €7T€l 8' OV TfTTjTLKQ. pLSV, €K TTjS 8' OLVTrjs 

vXrjs EOT i 7rdvTa, rj ei? to ovpoTrvyiov avTOis Tpo(/>r) 
20 €L$ to. OKeXrj KaTavaXiOKopLevrj TavTa rjvtjrjoev. Sto 


7T€tovtou yap airoTcivovTes els to oTTicrOev ovtqj yap 
avTols XPV <TL l xa r< * OKeXr), aXXcos 8' epiTToBi^otev av. 

Td Se fipaxvoKeXrj <Vd) OKeXrf irpds rfj yaaTpl 
€\ovTa neTOVTav tois fiev yap avTciov ovk ip7ToSt- 
25 £oucriv ol TroBes ovtoj, toTs 8e yafiipcovv^i Kal 7Tp6 
epyov elol Trpos TTjv dpTTayTjV . 

Tojv 8' lypvTOJV opvlOojv tov aO^eVa (xaKpov ol 

pi€V TTayVTtpOV €XOVT€$ TTETOVTai €KT€Tapi€V(Jj TO) 
aV)(€VLy ol $€. XeTTTOTCpOV* OVyK€KapLpL€VOJ ' €7TL7T€TO- 

fievois ydp Sid tt\v oKeTrrjv ijttov evBpVTTTOv eoTiv. 

695 a ICT^lOV 8* e^OUOT fJlkv Ol dpviBes HaVTeS fj OVK dv 

ho^aiev e^€iv, dAAd Svo fJirjpovs 8id to tov l&xtov 
pirjKOS' v7TOT€TaTai yap p>expi ^°" r }^ T V 9 yaoTpos. 


1 /cat Y6, Ogle : om. vulg. 

2 ra 6e fipaxvaKeXr} PY6 ; correxi : h'ta 8e fipaxea <ra Lang- 
kavel> qkcXtj vulg. 

3 Xeirrorepov Peck : Xctttqv kox fiaKpov vulg. : [/cat fiaKpov] 
seel. Rackham. 



are like oars to a sailor or fins to a fish. A fish that 
has lost its fins can no longer swim ; nor can a bird 
whose webs have been destroyed. 

Some birds have long legs, owing to their living in 
marshes ; for Nature makes the organs to suit the 
work they have to do, not the work to suit the organ. 
And these birds have no webs in their feet because 
they are not water birds, but because they live on 
ground that gives under them they have long legs 
and long toes, and most of them have additional joints 
in their toes. Furthermore, though these birds are 
not great fliers, they are composed of the same ma- 
terials as the rest, and thus the nutriment which in the 
others goes to produce the tail feathers, in these is 
used up on the legs and makes them grow longer, and 
when in flight these birds stretch them out behind 
and use them in place of the missing tail feathers : 
placed thus, the legs are useful to them ; otherwise 
they would get in the way. 

Short-legged birds keep their legs up against the 
belly while they are flying, because if the feet arc 
there they are out of the way ; the crook-taloned 
birds do it for an additional reason : the feet are 
convenient for seizing prey. 

When a bird has a long neck, this is either thick and 
is held stretched out during flight ; or it is slender 
and is bent up during flight, because being protected 
in this way it is less easily broken if the bird flies into 
anything. All birds have an ischium, but in such 
a way that they would not appear to have one ; it is 
so long that it reaches to the middle of the belly and 
looks more like a second thigh-bone. The reason for 
this is that a bird, although a biped, does not stand 



695 a 

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6 rot? rerpoLTTociLv, air 6 rrjs eSpas /3oa;(t> to ta^ior 
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iordvai. 6 pikv yap avBpumos 6p96v, tols Se re- 
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otcu. ol 8' opviOes ovk opOol fJL€V Sia TO VCLVtbheiS 

elvCLL TTjV (ftVGLVy OKeXr} 8' e/X77oda#ta OVK €)(OV- 

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7TOp€V€o9aL OVVTjTai Kal fA€V€lV. A St' 7]V {JL€V OVV 

alriav Slttovv iorlv ovk opBov 6v s eiprjTai' tov 8 
doapKa to. OKeXr) elvat r) avrr) atria Kal em tcov 
rerpaiToScov, vrrkp r}$ Kal rrpooOev eiprjrai. 

15 TerpaSaKTvXoL 8' etc J rravres ol opvides opioiios ol 
oreyavoTToSes tols ax^orroaiv {rrepl ydp tov arpov- 
dov rod Al/Svkov vcrrepov Siopiov^v, on Si^AoV, 
dfia tols Xolitols iravTLcofiaGLv of? e^et rrpos to tcov 
6pvi9cov yevos). rovrcov 8' ol pikv rpeis kparpo- 
oBeVy 6 8' et? ornodev rrpos dac^dXetav avn TTTepvrjs' 

20 Krai tcov fiaKpooKeXcov Xeirrei rovro Kara. fieyeBos, 
oiov avpLPefir]Kev irrl rrjs KpeKos' rrXetovs 8' ovk 
exovoL SaKrvXovs. 5 iirl fxkv ovv tcov dXXcov ovrcog 
rj tcov SaKTvXcov e^et diois y r] 8' a>y£ Suo fiovov 
rovs epLTrpocrdev Kal ovo tovs omoOev** alriov 

1 <of> Rackham, cf. 1. 14 infra. 

2 6Xws PQU, Ogle : opBov vulg. 

3 COrrexi ; Zxovaiv Bia rovro -nrtpvyas zx ovaw vu ^* (irr*pv~ 
yas, Se altero ex ovaiV omisso, Y, Ogle, qui post 8td rovro 



upright ; and if it had an ischium which extended 
only a short way from the fundament and was fol- 
lowed immediately by the leg (as in man and the 
quadrupeds), it would be unable to stand up at all. 
Man can stand upright, and quadrupeds have fore- 
legs to support their forward weight ; birds, how- 
ever, neither stand upright (because they are dwarf- 
like), nor have forelegs (because they have Mings in- 
stead). a By way of compensation, Nature has made 
the ischium long, reaching to the middle of the 
body, and has fixed it fast, while beneath it she has 
placed the legs, so that the weight may be equally 
distributed on either side and the bird enabled to 
walk and to stand still. This shows why birds are bi- 
peds although they are unable to stand upright. The 
reason why their legs are lacking in flesh is the same 
as for all quadrupeds and has been stated already. 6 

All birds, web-footed or not, have four toes on each 
foot. (The Libyan ostrich will be dealt with later, 
and its cloven hoof and other inconsistencies with the 
tribe of birds will be discussed.) Of these four toes, 
three are in front, and the fourth is at the back in- 
stead of a heel, for stability. In the long-legged 
birds this toe is deficient in length, as for instance in 
the Crex. Still, the number of toes does not exceed 
four. This arrangement of the toes holds good gener- 
ally, but the wryneck is an exception, for it has only 
two toes in front and two at the back. This is because 

a See above, 693 b 3 ff. 

* See 689 b 10 ff. 
c At the end of the book. 

4 fi€V€iv Yb : fiarrj vulg. 
6 Bta rrjv orevoT-qra tov okcAovs add. PY£>. 
6 Zfiirpoodev . . . omcrflev Karsch : oirtodzv . . . cfnrpoadcv vulg. 



695 a s s 

25 8' on ^rrcJv eariy a^T^s" to otofia irpoireTes enl to 
irpoaQev rj to tcov dXXcov. 

KJpXeis o exovoL fiev Travres oi opviues, evTos 
§' exovoiv r) 8* air la ev rot? irepl ras yeveoeis 
\ey6r\G€raL tcov ^cpcov. 
695 b Td fiev ovv tcov opvlOcov \xopia tov rpoTrov e^€t 


XIII. To 8e tcov IxOvcov yevog en fiaXXov KeKoXo- 
/3ajrat tcov eKTOs fioplcov. ovre yap UKeXrj ovre 
XeTpas ovre Tirepvyas k'xovcnv (etprjraL he rrepl tov- 
5 tcov rj atrta TTporepov), aAA' oAov airo rrjs KecfcaXrjs 
to kvtos Gvvexes euTi fiexP L Tr)s ovpas. ravTrjv 8' 
oi>x ofiolav e'xovai TrdvreSy dXXa rd fiev TrapaTrXrj- 
olav 3 l tcov he TrXarecov evia aKavOcohrf Kal fiaKpdv 
r) eKeWev yap av^rfais ylverat els to ttX&tos, olov 
eon vdpKats Kal rpvyoai Kal el tl tolovtov dXXo 
10 oe\axo$ eoriv. tcov fiev ovv toiovtcov aKavOcohes 
Kal fiaKpov to ovpaiov eariv, evlcov he aapKcohes fiev 
fipaxv he 8td rrjv avTrjv air lav St* rjvTrep Tat? 
vdpKai£- hiatpepei yap ovhev, rj fSpaxv fiev oapKco- 
heoTepov he> rj fiaKpov fiev daapKorepov §' elvai. 

'E—t he tcov fiarpdxcov to evavrlov GVfi$e$r\Kev 
16 Std yap to fir) oapKcohes etvai to nXdrog avrcov 
to efinpoodioVy ooov d^rjprjraL uapKcoSeg } Trpog to 
omodev avrcov 2 eOrjKev r) tfivcn$ Kal rrjv ovpdv. 

Ovk exovui §' aTTrjpTrjfieva KcoXa ol l^dves hid to 
vevoriKr)v elvai rrjv thvcriv avrcov Kara rov rfj$ 
ovolas XoyoVy eirel ovre rreplepyov ovhev ovre fidrrjv 

1 /xev aAAa tt. P : fikv dfiy tt. Piatt : fikv TTapaTrXrjata <toij 
7rr€pirytois) Ogle, similia voluit Thurot. 

2 clvtwv U : avro vulg. 

° See De gen, an. 714 b 4 ff., 719 b 11. 



the weight of its body tends forward less than that of 
other birds. 

All birds have testicles, but the)' are inside the 
body. The reason for this will be stated in the 
treatise on the different methods of generation 
among arrimals. a 

This concludes our description of the parts of Birds. (Hi.) Fishes : 

XIII. In the tribe of Fishes the external parts 
are still further stunted. Fishes have neither legs, 
hands, nor wings (the reason has been stated earlier), 
but the whole trunk has an uninterrupted line from 
head to tail. Not all fishes' tails are alike ; but the Tali, 
general run of them have similar tails, though some 
of the flat-fish have a long, spiny one, because the 
material for the tail's growth goes into the width 
of the flat body : this happens in the torpedo-fishes, 
in the Trygons, and any other Selachians of the same 
sort. These have long, spiny tails. Others have 
short, fleshy ones, and for the selfsame reason : it 
comes to the same thing whether the tail is short 
and has a good deal of flesh or long with little flesh. 

In the fishing-frog b the opposite has taken place. 
Here, the wide, flat part of the body in front is not 
fleshy ; Nature has taken the fleshy material away 
from the front and added an equivalent amount at 
the back — in the tail. 

Fishes have no separate limbs attached to the body. 
(a) This is because Nature never makes anything that 
is superfluous or needless, and by their essence and 
constitution fishes are naturally swimmers and so 

b Lophius piscatoritts, known as the " goosefish " in 
U.S.A., erroneously included by Aristotle (De gen. an. 
754 a 25) with the Selachia, though he observed that it 
differed in many important points. 

c Logos : see Introduction, pp. 26 f. 



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rropelas Kal Kivrjcreats Ttbv ^coojv etprjrai, r) yap 


1 tov avrov Peck : tovtov vulg. 

2 ol 6*<f>ets rov TpoTTOv Y6 : tov delevi : tov Tpoirov ol 6<j>€ts 

° The Cordylus was probably the larval form of some 
triton or newt, such as Triton alpestris or Salamandra atra, 
which retains its gills till it is well grown (D'Arcy Thompson). 

b i.e. pectoral. * i.e. ventral. 



need no such limbs. But also (b) they are essentially 
blooded creatures, which means that if they have four 
fins they cannot have any legs or any other limbs of 
the sort ; so they have the fins because they are 
swimmers and do not have the feet because they are 
not walkers (when an animal has feet it has them 
because they are useful for moving about on land). 
The Cordylus, a however, has feet in addition to its 
gills, since it has no fins, but only a scraggy flattened- 
out tail. 

Excluding flat-fish (like the Batos and Trygon), fish Fins, 
have four fins : two on their under and two on their 
upper surface, never more, for then they would be 
bloodless animals. Almost all fishes have the two 
upper b fins, but some of the large, thick-bodied fishes 
lack the under c two — as for instance the eel and the 
conger, and a sort of Cestreus that is found in the lake 
at Siphae. d Fishes that have even longer bodies than 
these, and are really more like serpents (as the 
Smyraena e ), have no fins at all, and move along by 
bending themselves about : that is, they use the 
water just as serpents use the ground. And in fact 
serpents swim in exactly the same way as they creep 
on the ground. The reason why these serpent-like 
fishes have no fins and the reason why serpents 
have no feet are the same, and this has been stated 
in the treatises on the Locomotion and Movement of 
Animals/ (a) If they had four motion-points, their 
movement would be poor, because the fins would 

d In Boeotia, on the south coast near Thespiae ; now 
Tipha. Aristotle refers to this Cestreus of Siphae again, 
De incessti an. 708 a 5. Cf. also Hist. An. 504 b 33. 

* Probably Muraena Helena. 

f See De incessu an. 709 b 7 ; perhaps the other passage 
which Aristotle has in mind is 690 b 16, in this book. 

o2 419 


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1 ra S* fjTTov . . . otov P : r/ Se tantum vulg. 
2 </xev> Langkavel. 



either be very close together, or else a long way apart, 
and in either case would not move easily. (6) On the 
other hand, if they had more than four motion-points 
they would be bloodless creatures. The same reason 
holds good for those fishes that have only two fins. 
These also are serpent-like and fairly long, and they 
use their power of bending instead of the two missing 
fins. And this enables them besides to crawl about 
and to live a good length of time on dry land ; and 
it is some while before they begin to gasp ; indeed, 
those which are akin to the land-animals are affected 
even less than the others. 

Except for those whose width and flatness prevents 
it, all fishes that have only two fins have the upper a 
ones ; and these fins are by the head., because there 
is no length of body just there which they could use 
instead of fins for propulsion — length such as fish 
of this sort have towards their tail-end. The Batoi 
and such fishes swim by means of the edge of their 
flat surface which they use instead of fins. Fish 
which are not so flat, such as the torpedo-fish and the 
fishing-frog, possess fins, but they have their upper 
fins toward their tail-end owing to the flatness of 
the forepart, and their under fins near the head (since 
the flatness of the fish does not prevent its motion) ; 
but the under ones are smaller than the upper ones, 
to make up for being placed forward. The torpedo- 
fish has two of his fins by his tail ; and instead of 
these two he uses the wide piece on each of his semi- 
circles b as though it were a fin. 

We have already spoken of the parts in the head 
and of the sense-organs. 

° i.e. pectoral. 
6 Cf. De incessu an. 709 b 17. 



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1 (xcn Spdhcavda yap) post irdvra vulg., om. P. 
2 77 Kivrjcris . . . vwdpd Y : at xriv-jjaeis . . . va>0pat vulg. 


The peculiarity which marks oft' fishes from the Gills, 
other blooded animals is the possession of gills. It 
has been explained in the treatise on Respiraiio?i a why 
they have them. All fishes have coverings over their 
gills, except the Selachia, none of which have them. 
This is because their bones are cartilaginous, whereas 
other fishes' bones are of fish-spine, and this is the 
substance out of which the coverings are made. And 
again, the Selachia move sluggishly owing to their 
lack of fish-spine — and of sinews — while the spinous 
fishes move quickly, and the movement of the cover- 
ing must be a quick one, for gills are a medium for 
expiration of a sort. On this account in the selachian 
group of fishes the passages of the gills can close up 
by themselves, and no covering is needed to make sure 
they close quickly. 

Now some fish have many gills, some have few ; 
some have double ones, some single. The last one 
is nearly always a single one. (For precise details 
consult the Anatomical treatises and the Researches 
upcm Animals?) The number of gills depends upon 
the amount of heat in the heart. The more heat an 
animal has, the quicker and stronger must be the 
movement of its gills ; and if the gills are numerous 
and double they are better adapted for this than if 
they are few and single. And on this account, some 
fishes (e.g. the eels and the serpentine fishes) which 
need but little cooling, as is shown by their having 
only a few weakish gills, can live a long time out of 

Fish differ also with regard to the mouth. Some Mouth, 
have their mouth right at the tip, straight in front ; 

• At 476 a 1 ff., 480 b 13 ff. 
b At 504 b 23 ff. 



696 b f - „ « > 

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1 SeA^a'e? non probant Frantzius, Ogle; similia Hist, An. 
591 b 26 secludunt Aubert et Wimmer. 

° This statement about dolphins, though repeated at Hist, 
an. 591 b 26, is incorrect, and as Aristotle was familiar with 


others have it underneath (e.g. the dolphin a and the 
selachians) and that is why they turn on to their backs 
to get their food. It looks as if Nature made them 
do this partly to preserve other animals from them, 
for they all prey on living things, and while they are 
losing time turning on to their backs the other things 
get away safely ; but she did it also to prevent them 
from giving way too much to their gluttonous craving 
for food, since if they could get it more easily they 
would presently be destroyed through repletion. 
Another reason is that their snout is round and small 
and therefore cannot have much of an opening in it. 

There are differences too among those that have 
their mouth above. With some it is a great wide 
opening (these are the flesh-eaters, as e.g. those with 
sharp interfitting teeth, whose strength is in their 
mouth) ; with others (the non-flesh-eaters) it is on 
a tapering snout. 

As for the skin : some have a scaly skin (these skin, 
scales are shiny and thin and therefore easily come 
loose from the body) ; others have a rough skin, e.g. 
the Rhine and the Batos and such. Those with 
smooth skins are the fewest. Selachia have skins 
which are scaleless but rough, owing to their bones 
being cartilaginous : instead of using the earthy 
matter on the bones Nature has used it for the skin. 

No fish has testicles b either without or within. Nor Testicles. 

the creature, some editors consider this reference to be an 

b By this Aristotle does not mean that fish have no organ 
for the secretion of sperm, but that they have no organ similar 
in shape and consistency to those of mammalia, etc. He calls 
the corresponding organs in fish not testes, but tubes, or roe. 
Aristotle's statement does not, of course, .include the Selachia, 
which have compact, oval testes. 



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TTvevpniov eyKecrac avroZs OeppLorrjros d)v 7rXrjpr]s 
alp,ariKrj$. eart ok ravra rporrov nvd (kol)* rre^d 

so Kal evvopa' rov pikv yap dipa Six^rac oj$ ire^d, 
a77oSa 8' earl Kal Xapcfidvei €K rov vypov rrjv 
697 b rpo<f)rjv ojorrep rd evvopa. Kal al (fyajKac 8k Kal 
at vvKrept^es Sid to iTrapL^orept^eiv at pikv roZ$ 
ivvSpois Kal 7tc^ol5, al Se toi? TrrrjvoZs Kal ire^ois, 
Sia tolto apL(j>orepcov re pitrixovoi Kal ovSerdptov. 

1 £<poTd*ca PSUY. 
* Kal (St77o8a Kal} Ogle. 
8 <*ai) Rackham. 



have any other footless animals, and this includes the 
serpents. In fish the passage for the residue and for 
the generative secretion is one and the same ; and 
this is so in all other oviparous animals, four-footed 
ones included. This is because they have no bladder 
and produce no liquid residue. 

Thus we have seen what are the differences to be inter- 
noticed in fish as a group as compared with other features : 
animals. Dolphins and whales and all such Cetacea, Cet& ^^ 
however, have no gills, but they have a blowhole 
because they have a lung. They cannot help letting 
the sea-water enter the mouth because they feed in 
the water, and once it has got in they must get it out 
again, and they do so through the blowhole. Gills, 
of course, are of service herein to those creatures that 
do not breathe. The reason for this has been given 
in my book on Respiration* 1 : no creature can breathe 
and at the same time have gills ; instead, these 
Cetacea have a blowhole for getting rid of the water. 
It is placed in front of the brain, otherwise it would 
separate the brain from the spine. The reason why 
these creatures have a lung and breathe is that large 
animals need more heat than others to enable them to 
move ; consequently they have a lung inside them 
full of heat derived from the blood. They are, in a 
way, land-animals as well as water-animals : they 
inhale the air, like land-animals, but they have no 
feet and they get their food from the water as water- 
animals do. Similarly, seals and bats are in an inter- (u.) Seals 
mediate position. Seals are between land-animals bat8 * 
and water-animals, bats between land-animals and 
fliers : thus they belong to both classes or to neither, 
a References given above, see on 696 b 2. 



5 at re yap (f>a>Kcu cos fiev evvSpot jrohas exovoiv, co? 
Se 7T€^at TTTepvyia 1 (tovs yap oTTivOev ttoSols l\dv- 


KapxapohoVTas Kal 6£eis) • Kat at vvKreptBes cos ficv 

TTTTjvd €"){OVOl TTohaS , COS T€TpOL7ToSa OVK tyOVOly 

/cat oure KepKov eyovoiv ovt ovpoTrvycov, Sta jxev 

10 TO TTTfjVa €LVai K€pKOV> Sta Se TO 77€^Ct ovpoirvyiov. 
uvfXp€^rjK€ S' auTat? tovt i£ dvdyKrjs' etcrt yap 
SeppLOTTTepoi, ovSev 8' e^et ovpoirvyiov fxrj a^t^d- 


TTvyLov. rj Se KepKOS Kal ifiTroSios av rjv virdpxovoa 


Tov avrov Se rpoirov Kal 6 OTpovdos 6 AifivKOS* 
is t<x (lev ydp opvidos £X €L > Ta ^ £<*>OV T€Tpa77oSo£. 
a>S" ftev yap ovk cov Terpdrrovs Trrepa e^et, cos S' 
ovk cov opvis ovre Trerarai fierewpi^ofievos s Kal rd 
7TT€pa ov ^p^crtjita irpds TrrfjoLV dAAd to^ouS^' eTt 
Be cos pi€v rerpaTTOvs cov ^Xe^aptSag k'^ei rds 
dvcoOev Kal ipiXos ion rd irepl ttjv K€<j)aXr]V Kal rd 
20 dvco tov avxevos, ware Tpix<*>oeoT€pas k'xeiv rds 
fiXecfcapihas s cos S* opvis cov rd Karcodev iTrreptoraL* 
Kal Slttovs {lev ioTLV cos opvis y St^aAos" S' cos 
rerpaTTOvs' ov ydp SaKTvXovs e^et dAAd x^Ads. 
tovtov §' aiVtov OTt to fidyeOos ovk opviOos 
dAAd TeTpa77oSos" * eAd^taTO^ yap dvayKalov etvai to 
25 fieyeOos cos KaBoXov elrreiv to tcov dpvldcov ov yap 
pdoiov ttoXvv oyKov Kiveiodai ocofxaTos fieTecopov. 

1 7TTepvyta Ogle : Trripvyas Vlllg. 



Seals, if regarded as water-animals, are anomalous in 
having feet ; if regarded as land-animals, in having 
fins (their hind feet are altogether like those of 
fishes — i.e. fins ; and all their teeth too are sharp and 
interlocking). Bats, too, if regarded as birds, are 
anomalous in having feet* 1 ; if regarded as quadrupeds, 
in not having feet & ; furthermore, they have neither a 
quadruped's tail (because they are fliers) nor a bird's 
tail (because they are land-animals). This their lack 
of a tail like a bird's is a necessary consequence, 
since they have membranous wings, and no creature 
has a tail of this sort unless it has barbed feathers : 
such tails are always made out of barbed feathers. 
And a tail of the other sort growing among feathers 
would be a definite impediment. 

After the same style is the Libyan ostrich: in (Hi.) The 
some points it resembles a bird, in others a quadruped. s 
As not being a quadruped, it has feathers ; as not 
being a bird, it cannot rise up and fly, and it has 
feathers that are like hairs and useless for flight. 
Again, as being a quadruped, it has upper eye- 
lashes, and it is bald in the head and the upper part 
of the neck, as a result of which its eyelashes are 
hairier than they would otherwise be ; as being a 
bird, it is feathered on its lower parts. Also, as 
a bird, it has two feet ; but, as a quadruped, it has 
cloven hoofs (it has hoofs and not toes). The reason 
is that it has the size not of a bird but of a 
quadruped. Speaking generally, a bird has to be 
very small in size, because it is difficult for a body of 
large bulk to move off the ground. 

a That is, of the sort that birds ought not to have, viz. on 
their wings. 

6 That is, of the sort that quadrupeds ought to have. 



Tlepl fi€V ovv twv fiopL(A>v, Sia tiv air lav eKOLGTOV 
ioTiv eV tols I^wols, elprjrai Trepl tt&vtwv twv ^cocdv 

Kdd* €KOL<JTOV TOVTOJV §6 hliX)piO\l£v(X)V i(f>€^7]9 €OTl 

30 ra Trepl rag yeveaetg avrcov SteXOeiv. 1 

1 rovrcov . . . SieAfleiv om. Yb t et statim incipiunt librum 
de incessu. 



We have now spoken severally of all the animals : conclusion, 
we have described their parts, and stated the reason 
why each is present in them. Now that this is 
concluded, the next thing is to describe the various 
ways in which animals are generated. 



Additional Note on 684 b 21-29 

Commentators agree that no satisfactory sense can be 
obtained from the first three lines of this passage as it stands 
in Bekker's edition. None has so far produced a remedy ; 
but an examination of the Arabic translation (or of Michael 
Scot's Latin translation made from the Arabic) shows plainly 
what has happened. In neither of these two translations is 
there any reference whatever to a diagram until 685 a 2. 
Thus the ms*. from which our present Greek text is derived 
had been corrupted through the efforts of someone who tried 
to improve the text of 6S4 b 22-27 by inserting references to 
a diagram here also ; and the result is that these references 
have caused the complete loss of one important phrase (b 22) 
and serious corruption of another (b 24-25). Some disloca- 
tion has also been caused in the lines following, up to line 29. 

The two diagrams given in the ms. Z are obviously con- 
structed to suit the interpolated text. One of the mss. (Mer- 
ton 278) of Michael Scot's version has an entirely different 
diagram ; the three mss. of Scot at Cambridge have no 
diagram at all, nor has the Arabic ms. B.M. Add. 7511. 

I give below the passage as it appears in Michael Scot's 

Natura ergo istorum duorum modorum est sicut diximus ; 
et propter hoc ambulant uniformiter 1 sicut accidit anhnalibus 
quadrupedibus et hominibus etiam. homo vero habet os in 
capite, scilicet in parte superiori corporis ; deinde habet 
stoinachum, deinde ventrein, et post ventrem intestinum per- 
veniens ad locum exitus superfluitatis. iste ergo res in 
animalibus habentibus sanguinem sunt secundum hanc dis- 
posit ionem, et post caput est clibanus, scilicet pectus, et quod 
vicinatur ei. alia vero membra sunt propter ista, etc. 

I am much indebted to Dr. R. Levy for his kindness in 
reading this passage for me in the Arabic in Brit. Mus. ms. 
Add. 7511. 

1 inuniformiter Caius 109 & Camb. U.L. Ii. 3. 16; fortasae igitur 
scribendum uniformiter et non inuniformiter. 



Additional Note on 693 b S 

Explanation of Aristotle's terminology for describing the 
bending of limbs. 
When Aristotle is speaking about the bending of limbs, 
backwards and forwards are relative to the direction in 

which the M'hole animal moves ; 
inwards and outwards are relative to the bulk of the body 

Thus, backwards means that the angle of the bent joint 
points backwards ; inwards means that the extremity of the 
limb is brought inwards towards the body, that is, the angle 
of the bent joint points away from the main bulk of the body. 
(" Inward " and "outward " bending thus have no connotation 
of " bandy-legs " and '* knock-knees.") 

All four legs bend inwards ; 
The forelegs bend forwards : 
The hindlegs bend backwards. 

The leg bends inwards, and 

(See Be incess. an. 711 a 8 ff., Hist. An. 49S a 3 ff.) 



Additional Note on the ms. Z 

The following portions of the text of De partibus are con- 
tained in the Oxford ms. Z (see p. 50) : 

fol. 60 r , 60 v . I. 639 b 29 to 640 b 24. pexpi to paXXov av 

fol. 61 r , 61 T . I. 644 a 25 to 645 a 17. wafloAov to rot? in- 

Between these two folios it has apparently lost four folios, 
as well as one at the beginning of Book I and another at the 

fol. F-19 r . Book II. 

fol. 19 v ~36 r . Book III, but the words ov ttoXv to evpvxtbpovs 
inclusive (675 a 30-b 27) are omitted, 
with no indication by the original scribe 
that anything has been omitted : this 
passage has been supplied by a later hand 
in the margins of fol. 35 v and 36 r and 
on 36 v . 

Book IV is written by yet another (later) hand, and this 
Book occupies fol. 37 r -59 v , at the end of which folio it breaks 
off at the words ra KaXovpeva (694 a 13). The rest of Book 
IV is lost. 

In the apparatus I have used the following abbreviations 
in quoting this ms. : 

Z Books I, II and most of III (first hand, c. a.d. 1000). 
Z 1 indicates the reading of the first hand where this has 

been altered by another. 
Z a indicates later correctors of Z 1 . 
Z indicates the readings of the ms. in Book IV. 

I have collated from photostats the whole of the portion 
written by the first hand, and the readings of Z quoted have 
been confirmed by reference to the photostats. 

I have used the symbol E when quoting the readings of 
E from 680 b 36 onwards, as this part of the ms. is written 
in a later hand. 




That the De incessu animalium is a genuine work of 
Aristotle himself has never been disputed. The De 
motu animalium has been regarded by many critics as 
a spurious work, though recent opinion has favoured 
its genuineness. Brandis, Rose and Zeller all con- 
demn it, but its Aristotelian authorship has been up- 
held by Werner Jaeger {Hermes, xlviii. pp. 31 ff.), who 
makes out a very strong case in its favour, and by the 
Oxford translator, Mr. A. S. L. Farquharson. Those 
who deny its authenticity rely mainly on the supposi- 
tion that there is a reference in 703 a 10-11 to the De 
spiritu. This treatise is generally admitted to be un- 
Aristotelian, but the reference, as Mr. Farquharson 
has pointed out, might relate equally well to numerous 
other passages in the Aristotelian corpus ; Michael 
Ephesius refers it to a treatise Uepl rpo^?, not 
otherwise known. In style, vocabulary and syntax 
the De motu animalium is entirely Aristotelian, and its 
doctrine corresponds with that set forth in Aristotle's 
genuine works. 

Each treatise has its proper place in the scheme of 
Aristotle's biological works. Both are theoretical, 
the De incessu animalium, like the De pariibus ani- 
malium, dealing with the material side of living things, 
and the De motu animalium, like the De generatione 
animalium) dealing with their consequential pro- 



The chief mss. of the De motu animalium are E, Y, 
P and S. a Of these E, one of the most famous of 
Aristotelian mss., is the oldest ; Y is closely related 
to E. P and S are similarly related and form a second 

Of the De incessu animalium the principal mss. are 
Z, Y, U, S and P.° Of these Z is the oldest, and Y is 
closely related to it, while the other three mss. form 
another group. 

A full account of these mss. and their relations to 
one another will be found in the Introduction (pp. 
iv. ff.) of W. W. Jaeger's text (Teubner, 1913). 

The text used for the present translation is based 
on that of I. Bekker, all divergences from which are 
noted and the authority given for the reading adopted. 
Jaeger's text and apparatus criticus have been con- 
sulted throughout. 

The Commentary of Michael Ephesius (Com- 
mentaria in Aristotelem Graeca, xxii. 2, Hay duck, 1904) 
has been of some assistance both for the text and for 
the interpretation, and the Latin version of Nicholaus 
Leonicus (died 1599)) printed in the Berlin Aristotle, 
Vol. Ill, has been constantly consulted. 

The two treatises have been translated into French 
by J. Barthelemy-Saint-Hilaire, and into English by 
Mr. A. S. L. Farquharson in the Oxford translation 
(1912). This translation with its ample explanatory 
notes constitutes much the most serious attempt that 
has been made to interpret these two treatises, and 
anvone who follows in Mr. Farquharson's footsteps 
must necessarily be heavily indebted to him. 

E. S. F. 

For the meanings of these symbols see pp. 439 and 483. 



Chap. I. The origin of all movement must itself be un- 
moved. So if there is to be animal movement, something 
in the animal must be at rest. Hence joints are necessary. 

II. There must also be a resisting medium external to the 
moving animal. Illustration from the rowing of a boat. 

III. The nature of the " prime mover." The fable of 

IV. The " prime mover " is of necessity outside the 
universe. The movement of inanimate things must 
originate from animate things. 

V. Alteration, growth, generation and corruption as 
forms of motion. 

VI. How does the soul move the body ? Animal move- 
ment lies in the sphere of action. Its limitation in com- 
parison with eternal movement. 

VII. Animal movement the result of the syllogism of 
action, not of the speculative syllogism. Animal move- 
ment compared with that of automatic toys. 

VIII. The psychology of animal movement and the 
organic changes which accompany it. The cause of move- 
ment must be situated in a definite origin. 

IX. The two sides of the body are similar and can move 
simultaneously : both are moved by the soul. 

X. The motive power is " innate spirit." Comparison 
between the animal organism and a well-ordered civic 

XI. Involuntary and non-voluntary movements. Con- 



E= Codex Parisinus Regius 1853. 

Y= Codex Vaticanus 261. 

P= Codex Vaticanus 1339. 

S = Codex Laurentianus 81. 1. 
Leon. = Latin translation of Nicolaus Leonicus. 
Mich. = Greek commentary of Michael Ephesius. 



698 a I. Uepl §£ KlVTf OeCOS TTjS rcbv ^LOCOV, Odd JJL€V 

avrcbv rrepl eKaarov virapx^ yevos, Kal rives 
Siacf>opai y Kal rives alrlai rcbv kclO^ eKaarov avfi- 
fiefirjKorcav at>rois s e-neaKeurai nepl dnavrcov ev 
erepois' SXcos oe Trepl rr^s Kotvqs air [as rod ki- 

5 veluOai Kivqaiv oiTOiavovv (ra fiev yap 7rrrjaei ki- 
veirai ra. Be vevaei ra oe rropela rcbv ^tocuv, ra. Se 
/car' dXXovs rporrovs roiovrovs) emaKeTrreov vvv. 

*'Ori fiev ovv dpx?) tcov dXXcov Kivrjaecov ro 
avro eavro kivovv, rovrov 1 8e ro aKivrjroVy 
Kal on ro rrptorov kivovv dvayKaiov aKivif]rov 

10 elvaiy Sicopiarai Trporepov, orerrep Kal rrepl Ki- 
vqaecos cuSiov, norepov eanv rj ovk early Kai ei 
eari 3 rls eanv, Bei Se rovro firj fiovov rcb Xoycp 
KaOoXov Xafieiv, dXXd Kal eirl rcbv Ka9* eWara 
Kal rwv aladi)rcbv, St' direp Kal rovs KaOoXov 
^rjrodfiev Xoyovs, Kal eft tov ecpapfxorreiv olofieOa 

is Beiv avrovs. cbavepov ydp Kal errl rovrcov on 
ahvvarov KivelaOai firjSevos rjpefiovvros, rrpcbrov 
{lev ev avrois rots ^toois* Set Y^Pj <*- v Kivrjrai ri 
rcbv jjioplcoVy rjpefieiv ri' Kal Sid rovro at Kajjnral 




I. We have inquired elsewhere a into the details of 
the movement of the various kinds of animals, the 
differences between these movements, and the causes 
of the characteristics which each exhibit ; we must 
now inquire generally into the common cause of 
animal movement of whatever kind — for some animals 
move by flight, some by swimming, some by walking, 
and others by other such methods. 

Now that the origin of all the other movements is 
that which moves itself, and that the origin of this is 
the immovable, and that the prime mover must neces- 
sarily be immovable, has already been determined 
when we were investigating 6 whether or not eternal 
movement exists, and if it does exist what it is. And 
this we must apprehend not merely in theory as a 
general principle but also in its individual manifesta- 
tions and in the objects of sense-perception, on the 
basis of which we search for general theories and 
with which we hold that these theories ought to 
agree. For it is clear also in the objects of sense- 
perception that movement is impossible if there 
is nothing in a state of rest, and above all in the 
animals themselves. For if any one of their parts 
moves, another part must necessarily be at rest ; and 

° In the De partibus animalium* 
b Physics viii. 258 b 4-9. 



rot? ^cools €lglv. ojairep yap Kevrpco xpcovrai 
rats KapLTTals, Kal ytverai to 6'Ao^ fiepos, iv a> rj 
20 KapLTTTj, Kal ev Kal ovo, Kal ev9v Kal K€Ka{XfieVOV, 
{jLerafiaXXov SvvdfieL Kal ivepyela Old ttjv KajjLTrrjv. 


arftieiov to oe fieveL tojv iv Tat? KajXTraiSy cocirep 
av el ttjs Stafierpov rj fiev A Kal r) A fievoL, rj oe 
B klvolto, Kal ylvotro rj AT. aAA' ivravda fiev 
25 ooKet TrdvTa TpoTTOv dhialpeTOV elvaL TO KevTpov 
(kol ydp to KiveiaQai) cos $aoi 3 ttX&ttovgiv iir 
avTobv ov ydp KiveTadai 1 tcov fiadrjfiaTLKtov 
ovSev), Ta S' iv Tats Kaparais SvvdfieL Kal ivepyela 
698 b ylverai ore fiev ev ore he oiatpeTa. aAA' ovv 
del r) apx 7 ? V ^pos o, rj 2 dpxrf, rjpefiei KLVovfievov 
rov fioplov tov KarwOev, olov tov fiev f$pax!>ovo$ 
Kivovfievov to wXeKpavov s oXov oe tov kcoXov 6 
cofjios, Kal tt)s fiev Kvrjfirjs to yovv, oXov Se rod 
5 OKeXovs to lax^'ov. otl fiev ovv Kal iv avTCp 
€KaaTov tl Set k'yew rjpefiovv, 66ev rj dpx^] 
rov KLVovfievov earaL, Kal Trpos o direpeioofievov 

1 KtveiaOa i ESY : kivcitcli P. 

* $ irpbs 6', $ Jaeger : 77 irpos 5 77 EY : 77 irpdoTtj S : 77 7rp6<ro) 
(om. altero a.pxi) P. 

e.g. the arm as an arm is one, but is divided into two at 
the elbow. 

6 The term apxrj, which occurs frequently in this treatise, 
is difficult to render in English by a single word. It is some- 
times used generally of the " origin " of movement {e.g. 
701 b33), but more often of a localized "origin" of movement, 


it is on this account that animals have joints. For 
they use their joints as a centre, and the whole part 
in which the joint is situated is both one and two, a 
both straight and bent, changing potentially and 
actually because of the joint. And when the part 
is being bent and moved, one of the points in the 
joint moves and one remains at rest, just as would 
happen if A and D in the diameter of a circle were 
to remain still while B moved, and the radius AC 
were formed. (In geometrical figures, however, the 

centre is considered to be 

in every respect indivisible — 

for movement, too, in such / 

figures is a figment, so they / >^ \ 

say, since in mathematics D[ ]B 

nothing actually moves, — \ / 
whereas the centres in the \ / 
joints are, potentially and >/ 
actually, sometimes one and 

sometimes divided.) Be that as it may, the origin 6 
to which the movement can be traced, qua origin,, 
is always at rest while the part below it is in motion 
— the elbow-joint, for instance, when the forearm 
is in motion, the shoulder when the whole arm is 
moved, the knee when the shin is moved, and the 
hip when the whole leg is moved. It is obvious, then, 
that every animal too must have in itself something 
that is at rest, in order to provide that which is 
moved with the origin of its movement, supported 

whether, as here, in a single member, or at the centre of the 
body, viz. the heart (701 b 25, 29), where a further idea of 
'* ruling " seems to be implied {e.g. 702 a 37). It is also used 
sometimes in the literal sense of " beginning," and this and 
the meaning" of " origin " of motion may occur in the same 
passage and cause confusion {e.g. 702 a 36-b 2). 

p 443 


Kal oXov adpoov Kiv7)Qr}0€Tai Kal Kara fiepog, 

II. 'AAAa rraoa r) iv avrto rjpefiia Spews aKVpos, 
av jiTj ri e£a)9ev fj dnXwg r)pepL0vv Kal aKivrjrov. 
10 d£iov §' iTnarrjaavras inLGKeifjaodaL rrepl rod 
XexOevrog- e^ei yap rrjv decopiav ov pLovov ogov 
IttI ra ^cool GwrelvovGav, dXXd Kal irpog Tr)v rod 
iravTog Kiv-qoiv Kal (f>opdv. djairep yap Kal iv 
aura) Set ri aKivrjrov etvai, el pceXXec KivetoOai, 
ovtws en ptdXXov e£a> Set re eivai rov £a>ov 


ptevov. el yap viroodxiei del, otov rots fxvcrl 1 rots 
iv ty} yfj 2 rj rolg iv rfj apptp TfopevopLevocg, ov 
TTpoeiGiv, otjS' carat ovre rropela, el per) r) yrj \xevoi s 
ovre irrrjcris rj vevGig, el fir) 6 drjp r] rj OdXarra 
avrepetooL. dvdyKr] Se tovto erepov etvai rov 
Kivovfievov , Kal oXov oXov, Kal [lopiov parjSev etvai 
20 rod KivovfJLevov to ovto>s aKLvrjTOV el oe fir], ov 
KLvrjOrjoeraL. fxaprvpcov Se tovtov to aTropov- 
puevov, Bid ti rrore to ttXolov e£a>9ev pcev, dv Tig 

(l)6fj TO) KOVTO) TOV LGTOV rj TL dXXo 7TpOGpdXXa)V 

pLopiov 3 Kivel paSlcog, edv 8' iv avrcp rig wv ra> 
ttXolo) tovto Treip&Tai rrpaTTecv, ovk av Kivr\Geiev 
25 ovt dv 6 TcTVog ov8* 6 I$opeag irvewv eGO)6ev iK 
rov nXoiov, el Tvypi Trvecov tov Tpoirov tovtov ov' 

1 fivfflv libra : e^vat coni. Diels. 
2 75 libri : £eiq. coni. Farquharson. 

° It is doubtful whether the ms. reading will bear this 
interpretation, and iv ry yy is probably corrupt. It is more 



upon which it will move both as an integral whole 
and in its several parts. 

II. Any quality of rest, however, in an animal is of 
no effect unless there is something outside it which is 
absolutely at rest and immovable. And it is worth 
while to stop and consider this dictum ; for the re- 
flection which it involves applies not merely to animals, 
but also to the motion and progression of the universe. 
For just as in the animal there must be something 
which is immovable if it is to have any motion, so 
a fortiori there must be something which is immov- 
able outside the animal, supported upon which that 
which is moved moves. For if that which supports 
the animal is to be always giving way (as it does when 
mice walk upon loose soil a and when persons walk on 
sand), there will be no progress, that is, no walking, 
unless the ground were to remain still, and no flying 
or swimming unless the air or sea were to offer resist- 
ance. And that which offers resistance must be other 
than -that which is moved, the whole other than the 
whole, and that which is thus immovable must form 
no part of that which is moved ; otherwise the latter 
will not move. This contention is supported by the 
problem : Why can a man easily move a boat from 
outside if he thrusts it along with a pole by pushing 
against the mast or some other part of the boat, 
but if he tries to do this when he is in the boat 
itself, Tityus could not move it nor Boreas by blow- 
ing from inside it, if he really blew as the artists 

than likely that the comparison is with a mouse trying to 
walk upon a heap of corn. Farquharson emends tv ttj yi} to 
iv rrj frig, which would bear this meaning. (The form 
cp. Petrie Pap. ii. p. 69 (3rd cent, b.c), would be nearer to the 
jvis. reading.) Diels' suggestion of k^xvoiv for fivatv is in- 
genious, but does not give the required sense. 



7T€p 01 ypacpeis ttolovolv olvtov yap to rrvevfia 
699 a d<f>i€vra ypa<f>ovoiv. edv re ydp rjpefia pLTrrfj to 
TTvevixd tls idv t layvp&s ovtws c5ot* dvefiov 

7TOL€LV TOV fliyLGTOV, Idv T€ <xAAo TL fj TO pLTTTOV ~ 

fievov rj cLOovfievov, drdyKrj irpcoTov fiev rrpos 


5 etra TrdXtv tovto to jiopiov, i*j avTO rj ov Tvy\av€L 

fl€V€LV. 6 §6 TO TtXoLOV (LOdjV Iv TO) TtXoLCx) OLVTOS 

<jov /cat aTTOGTrjpi^ofjLevos Trpos to ttXolov evXoycos 
ov klvel to ttXoXov Sta to dvayKatov €lvoll Trpos o 
d7T0UTr)pL^€TaL fxiveLv crvfifioLLveL S* avTW to clvto 

10 6 T€ KLV€L KOL TTpOS O dTTOGTrjpL^eTOLL . €^(X)9€V S' 

cbQwv rj eXkojv KLvei' ovOev yap fiepos rj yrj tov 

III. y A7TOprjCF€L€ S' O.V TL$ t dp* €L TL KLV€L TOV 

oXov ovpavov, etvat T€ Set aKLvryrov tovto /cat 1 
firjOh' etvaL tov ovpavov \iopLov /.t^S' iv to> 
ovpavu). €LT€ ydp avTo KLVovfxevov KLvel avTov, 
15 dvdyKT] tlvos aKLvrjTov BLyydvov klvclv, /cat tovto 

p.7]$€V €Ll>aL fJLOpLOV TOV KLVOVVTOS' €LT* €v6l)S dhCLVTjTOV 

fievov [LopLov. /cat tovto y* 6p8d)s XeyovoLv ol 
XlyovTes otl kvkXco <f>epopi4v7]s Trjs o<f>aLpas ouS' 
otlovv fjLeveL {JLopLov rj yap dv SXr]v dvayKalov rjv 
20 jJL€V€LV } rj hiaoTTaoOaL to uvvc^ks ai>Trjs. dAA' 


1 tovto Kal scripsi : kclI tovto libri. 
1 fVrat Jaeger (cum Leon.): Zaeadai libri. 

° Just as Odysseus' companions while seated in the ship 
open the bags containing the winds, and the ship is blown 
out of its course (Homer, Od. x. 46 ff,). 



paint him a ; for they make him emit the breath 
from his own lips. For whether one emits the 
breath gently or so strongly as to create the greatest 
gale (and the same is true if that which is thrown 
or pushed is something other than breath), it is 
necessary, first, that one should be supported upon 
one of one's own members, which is at rest, when one 
pushes, and secondly, that either this member itself 
or that of which it forms part, should remain still, 
resting upon something which is external to it. Now 
the man who tries to push the boat while he himself 
is in it and leaning upon it, naturally does not move 
the boat, because it is essential that that against 
which he is leaning should remain still ; but in 
this case that which he is trying to move and that 
against which he is leaning, is identical. If, on 
the other hand, he pushes or drags the boat from 
outside, he can move it ; for the ground is no part of 
the boat. 

III. The difficulty may be raised, whether, if some- 
thing moves the whole heaven, this motive power 
must be unmoved and be no part of the heaven nor 
in the heaven. For if it is moved itself and moves the 
heaven, it can only move it by being itself in contact 
with something that is immovable, and this can be no 
part of that which causes the movement ; or else, if 
that which causes the movement is from the first im- 
movable, it will be equally no part of that which is 
moved. And on this point at any rate they are quite 
right who say that, when the sphere is moved in a 
circle, no part of it whatsoever remains still ; for 
either the whole of it must remain still, or its continu- 
ity must be rent asunder. They are not right, how- 
ever, in holding that the poles possess a kind of force, 



699 a v 

exovras ixiyeOos dAA' ovrag ecr^ara /cat orty/xds 1 , 
ov kolXojs. 7Tp6s yap ra> yaqhepiLav overlap elvai 
rwv tolovtcov {irjSei'os, Kal KiveioBai rrjv \iLav 
klvtjglv V7t6 Svoiv dovvaTOV tovs Se 7roAofS" Suo 

25 TTOIOVCTLV. OTl fJL€V OVV €){€l Tt Kal 77/30? TTJV oXrjV 

<f)V(7LV ovtqjs worrep r) yrj npos tcl £cua /cat ra 


oiairopr)(J€i€v. ot Se fJLvBiKQJS tov "KrXavra 
TTOiovvres eVt rrjs yfjs e^ovra rot's* rrooag oo^atev 
dv a7ro oiavoLas elprjK€vai tov fxvOov, cos* tovtov 
a)G7T€p hiafxerpov ovra Kal arpi^ovra tov ovpavov 
so Trepl tovs ttoXovs' tovto S' dv avfifialvoi KaTCL 
Xoyov Std to ttjv yrjv jxiveiv. dXXa rots* TavTa 
Xeyovoiv dvayKaiov (f>dvai fxrjSev arat \xopiov 
avTTjv tov iravTos. rrpos Se To^rots' Set Tr)v Ig)(vv 
Ivd^eiv tov KtvovvTog Kal rrjv tov jiivovTos • ecrrt 
yap rt TrXrjdos lgxvos Kal Swdfietos /ca#' rjv fiivet 

35 TO (JLeVOVy 6007760 Kal KaO' TjV KLV€L TO KLVOVV Kal 

€gtl Tis dvaXoyia i£ dvdyKrjs, wanep tojv evavTiajv 
KivrjGewv, ovto) /cat twv r)pefjua)v. Kal al fiev 
699 b tcrat aVa^ts* U7J-' dAArJAoji^ KpaTOVVTac Se /card 
ttjv vTrepoxrfv. htoirep etr' "ArAas- €lt€ tl tolovtov 


avTepelSeiv Set ttjs jiovrjs rjv rj yrj Tvyxdvei jilvovaa- 
r) Ktvrj6r}G€Tac r) yrj drro tov fiecrov Kal Ik tov 
5 avTrjs tottov. cos* yap to ojOovv ajdei, ovtoj to 
(LOovfJievov (hQeiTat) Kal oyioiajs tear* lgxvv. KtveX 

i.e. their limbs. We should, however, perhaps read 5l 
clvtuv " the things which move of themselves": Leon, 
renders "ea quae per se moventur." 


since they have no magnitude and are only ex- 
tremities and points. For besides the fact that 
nothing of this kind has any substance, it is also im- 
possible for a single movement to be started by a dual 
agency ; and they represent the poles as two. From 
these considerations one may hazard the suggestion 
that there is something which stands in the same 
relation to Nature as a whole as the earth stands to 
the animals and the things which are moved through 
them. a 

Now those who in the fable represent Atlas as hav- 
ing his feet planted upon the earth would seem to 
have shown sense in the story which they tell, since 
they make him as it were a radius, twisting the 
heaven about the poles ; it would be a logical account, 
since the earth remains still. But those who hold 
this view must declare that the earth is no part of the 
universe ; and, further, the force of that which causes 
the motion and the force of that which remains still 
must be equal. For there must be a certain amount 
of force and strength in virtue of which that which 
remains still remains still, just as there is a force in 
virtue of which that which causes motion causes 
motion ; and there is of necessity a similar proportion 
between absences of motion as there is between 
opposite motions, and equal forces are unaffected by 
one another, but are overmastered by a superiority. 
Therefore Atlas, or whatever else it is of like kind 
within that causes motion, must not exert any pressure 
which is too strong for the equilibrium of the earth ; 
or else the earth will be moved away from the centre 
and her proper place. For as that which pushes 
pushes, so that which is pushed is pushed, and in 
exact proportion to the force exerted ; but it creates 




r) Igxvs rj 6[xota Kal tarj rrjs r)peybtas. (Laavrcog 
he Kal rrjs 1 tov Kivovfievov \xev y fir) klvovvtos he. 
roaavTrjv ovv herjaet rrjv hvvajiiv elvai rrjs yrjs 

Iv TO) r)p€fX€LV OGTjV 6 T€ 7TCLS OVpOLVOS €X €t KCIL 

10 to klvovv avrov. el Be tovto dhvvaT0v t ahvvaTov 
Kal to KLvelodai tov ovpavov vtto tlvos tolovtov 
twv evros* 

IV. "Eo*Tt he tis aiTOpla Trepl rag Kivrjaeis twv 
rod ovpavov [iopitov y r\v d>s ovcrav oweiav toXs 
elprjixevois emGKeiftaiT dv tl$. eav yap rig vrrep- 
fidXXrj rfj hwdpLec rrjs Kivrjcrews rrjv rrjs yrjs 

15 -qpefilav, hrjXov on Kivqaet avrrjv oltto rod fieaov. 
Kal r) laxvs 8' aft rjs avrr) r) hvvafiLS, on ovk 
onTeipos, <f>avep6v ovhe yap r) yrj direipoS) coot 
ovhe to fidpos avrfjs. enel he to ahvvaTov Xeyerai 
TrXeovax&s {ov yap wcravTWS Tfjv re cfyojvrjv ahvvaTov 
<j)afiev elvai opaOrjvai Kal tovs errl Trjs aeXrjvrjs 

o vft rjiicbv to fiev yap e£ dvdyKrjSy to he ire^vKos 
opdaOat ovk 6<f)6r)creTai) , tov 8' ovpavov d<f)6apTov 
elvat Kal dhcdXvTOv olofxeOa fiev e£ dvdyKirjs eivai, 
oviJifiaLvei he Kara tovtov tov Xoyov ovk e£ dvdyKrjs' 
7re<f)VKe yap Kal evhex^Tai elvai KivrjULV fiei^oj 
Kal aft rjs rjpefiet r) yrj Kal aft rjs Kivovvrai to 

o$7Tvp Kal to avoj acdfia. el fiev ovv eioiv at virep- 
exovoai Kivrjcreis, hiaXvOrjoeTai Tavra vtt* dXXrjXwv. 

1 ri]s PS : rj Y : at E. 

a i.e. its central position in the universe. 

6 i.e. the region between the air and the moon (Meteor. 
340 b 6 ff.). 


motion in that which is first at rest, so that the force 
exerted is greater than the immobility rather than 
similar and equal to it, and likewise greater than the 
force of that which is moved but does not create 
movement. Therefore the power of the earth in its 
immobility will necessarily be as great as that pos- 
sessed by the whole heaven and that which sets it in 
motion. If, however, this is impossible, the move- 
ment of the heaven by any such force within it is also 

IV. A problem also arises about the movements 
of the parts of the heaven, which might well be dis- 
cussed, since it is closely connected with what has 
been said above. If one were to overmaster the im- 
mobility of the earth by the power of motion, one will 
obviously move it away from the centre. Moreover 
it is clear that the force from which this power is de- 
rived is not infinite ; for the earth is not infinite, and 
so its weight is not infinite either. Now the word 
" impossible " is used in several senses (we are using 
it in different senses when we say that it is impossible 
to see a sound, and when we say that it is impossible 
for us to see the men in the moon ; for the former is 
of necessity invisible, the latter are of such a nature 
as to be seen but will never be seen by us), but we 
hold that the heaven is of necessity impossible to 
destroy and dissolve, whereas according to our present 
argument it is not necessarily so ; for it is within the 
nature of things and the bounds of possibility that a 
motive force should exist greater both than that 
which causes the earth to be at rest and than that 
which causes the fire and upper body b to move. 
If, therefore, the overpowering motive forces exist, 
these will be dissolved by one another; but if they 



el Se firj elul fiev, eVSe^ercu §' etvai {aireipov ydp 
ovk ivh£x erai $ La T ° P-rjSev ucofia evhixeudai 
aireipov elvai) y iv8ex otT * av BiaXvOrjvai tov ovpavov. 
tl yap KcoXvei tovto avjjLfirjvat, eiTrep firj ahvvarov ; 
ovk aovvarov be, et fir] TavTiKetfievov avayKaiov. 
dAAd rrepl fiev rrjs airoplag Tavrrjs erepog ecrrco 

*Apa Se Set olklvtjtov tl elvat Kal rjpepiovv e£to 
rod KivovfjLevov, [xrjSev ov eKelvov fxoptov, 77 ov; 
Kal tovto rtoTepov Kal inl TOV TTaVTOS OVTLOS 
virapyew avayKaiov ; luojs yap av So^etev cLtottov 
35 elvaiy el rj apXQ r V s KL\"quea)s evTos. hid 86£eLev 
av toIs ovTOjg V7roXapi^dvovGLv ev elpfjcrOai 'Ofitfpcp* 

dAA' ovk av ipvoaiT i£ ovpavodev 77eStWSe 
700a TJqv^ viraTOV tt&vtoov , ouS' el /.idAa rroXXa KapiOLTe' 
TrdvTes 8' e^drrTeaOe 6eol 77a<rat Te Oeaivai. 

to yap oXqjs aKivr^TOV vtt* ovhevos ev&eyeTai 
Kivrjdrjvai. 69ev XveTai Kal rj irdXai Xe)(0etcra 
arropia, rroTepov ivhi^erat rj ovk eVSe^erat Sta- 
5 Xvdfjvat ttjv tov ovpavov ovoTaoiv, el it; aKivrjTov 
rjpTrjTai apxrjs* 

'Em Se twv l^cpajv ov fiovov to ovtojs aKLvtyrov 
Set VTtapyeiv, dAAa Kal ev avTOis tois KLvovyiivoLS 

° dweipov] sc. Kivrjviv. The argument is as follows: these 
overpowering motive forces might exist and be dissolved by 
one another, because if they can be dissolved, they are not 
infinite, and the reason why they are not infinite is that they 
act upon what is finite, and the infinite cannot act on the 
finite (De caelo, 274 b 23 ff.). 

b It is discussed in the Physics and De caelo. 


do not really exist, but there is a possibility of 
their existing (for an infinite motive force a is impos- 
sible because an infinite body is also impossible), 
it would be possible for the heaven to be dissolved. 
For what is there to prevent this happening if it 
is not impossible ? And it is not impossible, unless 
the opposite proposition is inevitable. But let us 
leave the discussion of this question for another 
occasion. 6 

Must there, then, or must there not, be something 
immovable and at rest outside that which is moved 
and forming no part of it ? And must this be true 
also of the universe ? For it would perhaps seem 
strange if the origin of motion were inside. And so 
to those who hold this view Homer's words would 
seem appropriate : 

Nay, ye could never pull down to the earth from the 

summit of heaven, 
Zeus, the highest of all, no, not if ye toiled to the utmost. 
Come, ye gods and ye goddesses all, set your hands to 

the hawsers. 

For that which is entirely immovable cannot be 
moved by anything. And it is here that we must 
look for the solution of the problem stated some time 
ago, namely, whether it is possible or impossible for 
the composition of the heaven to be dissolved, seeing 
that it depends upon an origin which is immovable. 

Now in the animals there must exist not only that 
which is immovable in this sensed but there must 
also be something immovable in the actual things 
which move from place to place and which themselves 

c Iliad viii. 20-29. The lines are quoted in the wrong 
order and the textus receptus reads firjaTup* for ttclvtojv. 

d i.e. something immovable and at rest which is outside 
that which is moved and forms no part of it (cf. 699 b 32). 



Kara tottov oaa Kivel avra avrd. Set yap avrov 
to }X€V r)p€fjL€LV to Se KiveiaOai, rrpos o aTrepeiho- 

10 [xevov to Kivovjxevov KivrjaeTaL, olov av ti Kivfj 
Ttov {Aopicov aTrepeLoeTai yap daTepov d>s npos 
\iivov OaTepov. Trepl Se Ttov aipv)(ajv Sera KiveiTai 
aTroprjaeiev av Tig, TroTepov airavT k'xei iv eavTots 
Kal to rjpefjiovv Kal to klvovv, Kal Trpos twv 
e£a> tl rjpepLovvTOJV aTrepeioeaQai dvdyKrj Kal 
rauTdj rj dovvaTov, olov irvp rj yrjv r] Ttov dipvx&>v 

15 tl, aAA n v<f>* ojv TavTa KiveiTai TTpwToyv. irdvTa 
ydp vtt* dXXov KLvetTaL ra ai/jv^a, dpx^} oe irdvTOJv 
tlov ovtws Kivovfxevwv ra aura aura KivovvTa. 


yap TocavTa TrdvTa dvdyKrj Kal iv avTOis e'xeiv 
to rjpepiovv, Kal e£w 7Tp6$ aTrepelaeTai. el Si 
20 ti iaTiv dvajTepaj Kal Trpa)TO>s klvovv, aorjXov, 
Kal aXXos Xoyos Trepl tt)s TOLavTTjs dpxfjs* Ta 
he £aia oaa KLveiTai, irdvTa Trpos ra e£a> drrep- 
€i86jJL€va KiveiTaiy Kal dvarrviovTa Kal iKtrviovTa. 
ovhev yap $ia<f>epeL \iiya piiftai fidpos 7) puKpov, 


25 eiGirviovTes Kal iK7TvioVT€$ . 


jjlovo) Set tl puiveiv, r] Kal iv tw aXXoiovfiiva) avTtp 
v<f>* avTov Kal av^avopLevtp ; Trepl Se yeveaeoos 
Trjs i£ dpxfjs Kal <f>Qopas dXXog Xoyog* el ydp iaTiv 
1 dXX' Jaeger: dXXaP: dXX' ESY. 



move themselves. For while one part of the animal 
must be in motion, another part must be at rest, 
supported upon which that will be moved which 
is moved, if, for example, it moves one of its parts ; 
for one part rests on another part in virtue of the 
fact that the latter is at rest. 

But regarding inanimate things which are moved, 
one might raise the question whether they all possess 
in themselves both that which is at rest and that which 
creates movement, and whether they too must be 
supported by something external which is at rest. 
Or is this impossible — for example, in the case of 
fire or earth or any inanimate thing — but motion is 
due to the primary causes by which these are moved ? 
For all inanimate things are moved by something else, 
and the origin of all the things that are thus moved is 
the things that move themselves. Among things of 
this class we have already dealt with animals ; for all 
such things must necessarily have within themselves 
that which is at rest and something outside them on 
which they are to support themselves. But whether 
there is something higher and primary which moves 
them is uncertain, and the question of such an origin 
of movement is a matter for separate discussion. But 
animals which move all do so supported upon things 
outside themselves, as also when they draw their 
breath in and out. For it makes no difference whether 
they propel a great or a small weight, as those do who 
spit and cough, and breathe in and out. 

V. But is it only in that which moves itself in 
respect of place that something must remain at rest, 
or is this also true of that in which alteration is 
caused by its own agency and in that which grows ? 
The question of original coming into being and 



700a a « > * - 

TjVTT€p <pafX€V TTpCUTT] KLVTjGLS, yevecretOS KCU <pVOpa$ 

30 avrrj air la av e'er), Kal tojv oXXojv he. Kivrjaewv igojs 
naacov. djcrirep 3* ev rw oAo», Kal ev tqj ^uhi) 

KLVTjCTlS TTpCOTT) aVTT] ) OTCLV reXew6fj m WOT€ Kal 

av^rjerews , ei rrore yiverai, avro avra> airiov Kal 
aXXoiwaeajs, el he. [j,rj y ovk dvdyKrj. ai he rrpwrai 
av^rjoeis Kal dXXoiwoeis vtt* dXXov yivovrai Kal 
35 St' erepwv yeveaews Se Kal <f>6opas ovhafiws otov 
700 b re avro alriov elvai avra> ovhev. rrpovrrapyew 
yap heT ro kivovv rod Kivovfievov Kal ro yevvwv 
rod yevvwfievov avro §' avrov rrporepov ovhev 
ear iv . 

VI. Uepl fxev ovv ifivxrjs, elre Kiveirai r) jjirj, 
5 Kal el Kiveirai, ttcos Kiveirai, rrporepov eiprjrai ev 
rots hicopicrpievois rrepl avrrjs. eirel he rd diffusa 
rrdvra Kivelrai v<f>* erepov, Trepl he 1 rod rrpwrov 
Kivovfievov Kal del Kivovjxevov, rLva rporrov Kiveirai, 
Kal ttcos Kivei ro irpwrov kivovv, hicopiarai rrporepov 
ev rois irepl rrjs Trptorrjs (f> iXo aocf) las , Xoittov 8' 
io earl Oetoprjcrai ttcos ?] Kivei r ^> crcofxa, Kal 

rls dpxr) rrjs rod ^coov Kivrjoetos. rcov yap dXXwv 
rrapd rr)v rod oXov Kivrjcriv rd efxiftvxa curia rrjs 
Kivrjcrecos, oaa fxrj Kiveirai vtt* dXXrjXcov hid ro 
rrpoGKorrreiv dXArjXois. hid Kal rrepas exovaiv 
avrtov iraaai ai Kiv-qaeis* Kal yap Kal ai rcov 
15 ifAifjvxajv. rrdvra yap rd ^cpa Kal Kivei Kal 
Kiveirai eveKa rivos, coare rodr eoriv avrois 
Trdcrqs rrjg Kivrjcrecos Trepas, rd ov eveKa. opcofiev 
1 8t ES : ixh Y. 

° tovt£<jtiv . . . ovk avdyKT} eXval ri tQp clWoiov/m^wp Kal 
(xv^avofxivicv v<f> avrwv r)pefxovp (Mich.). 

b i.e. the Metaphysics. 


corruption is a different one ; for if there is, as we 
assert, a primary movement, this would be the cause 
of coming into being and wasting away, and per- 
haps of all the other movements as well. And as in 
the universe, so in the animal, this is primary motion, 
when the animal comes to perfection ; so that it is 
itself the cause of its own growth, if this ever takes 
place, and of any alteration which occurs ; otherwise 
it is not necessary that something should remain at 
rest. a But the first growth and alteration occur 
through another's agency and by other means, and 
nothing can in any way be itself the cause of its own 
coming into being and wasting away ; for that which 
moves must be prior to that which is moved, and that 
which begets to that which is begotten, and nothing 
is prior to itself. 

VI. Now whether soul is moved or not, and if 
it is moved, how it is moved, has already been 
discussed in our treatise On Soul. But since all 
inanimate things are moved by something else — and 
how that which is primarily and eternally moved is 
moved, and how the prime mover moves it, has been 
already set forth in our work on First Philosophy b — 
it remains to inquire how the soul moves the body 
and what is the origin of movement in an animal. 
For, if we exclude the movement of the universe, 
animate things are the cause of movement in every- 
thing else, except in things which are moved by one 
another through coming into collision with one 
another. Therefore all their movements have a 
limit ; for the movements of animate things have a 
limit. For all animals move and are moved with 
some object, and so this, namely their object, is the 
limit of all their movement. Now we see that the 



ok ra Kivovvra to t,aJov ^>Lavoiav Kal <f>avTaalav 
Kal TTpoalpccriv Kal fiovXrjGLV Kal irudvpLiav. ravra 
8k Trdvra avdyerat els vovv Kal opt^iv. Kal yap 
20 rj jyavraaia Kal rj aluOiquis ttjv avT-qv ra> vw ^cupav 
€)(ovgiv KpiTiKa yap Trdvra, Stacfyepovon Se Kara 
rds eiprjjjLevas iv aXAois oiacf>opds. fiovXrjcns Se 
Kal Ovpios Kal eTTtdvfJLLa Trdvra ope^is, rj Se irpo- 
atpecris kolvov oiavolas Kal opi^eojs' ojot€ KiveZ 


25 Se to oiavoiqTOVy dXXa to tojv irpaKTWV ri\os. 
016 to tolovtov l(7Ti tojv dyaOwv TO kivovv, aAA' 
ov irav to KaXov fj yap eVexra tovtov aXXo, Kai 


KLvet. Set ok TiOivat Kal to (JjaivopLevov dyaOdv 
dyaOov yojpav e^etv, Kal to rjov* (j>aiv6jJL€vov yap 
30 ioTiv dyaOov. ojutz SrjXov otl eoTi p,kv fj ofiocws 
/avetrat to del KivovpLevov vtto tov del klvovvtos 
Kal tojv ^ojojv eKaoTov, euTL 8' fj dXAojs, 8 to /cat 
ra fikv del /avetrat, rj ok tojv X^ojojv Kivrjacs e^et 
nepas. to 8e dtSiov KaXov, Kal to dXrjOojs Kal 
rrpojTCos dyadov Kal pLrj ttote p,kv 7tot€ ok prq, 

35 0€LOT€pOV Kal TLfJLLOJT€pOV TJ COOT* €ivai 7TpOT€p6v l TL 2 . 
701 a Ope£tS Kal TO OpeKTLKOV KLVOVpL€VOV KlV€l. to Se 

TeXevralov tojv KivovjjLevwv ovk dvdyK-q Kivelv 
ovhev. (jjavepov 8' Ik tovtojv Kal ort evXoytos 

1 irpbrepov ESY : irpbs 'irepov P. 
2 tl add. Jaeger. 


De anima, iii. 427 b 14 ff. 


things which move the animal are intellect, imagina- 
tion, purpose, wish and appetite. Now all these can 
be referred to mind and desire. For imagination 
and sensation cover the same ground as the mind 
(since they all exercise judgement) though they 
differ in certain aspects as has been defined else- 
where. But will, temper, and appetite are all 
forms of desire, while purpose partakes both of 
intellect and of desire. So the objects of desire and 
intellect first set up movement — not, however, every 
object of intellect, but only the end in the sphere of 
action. So amongst good things it is the good in the 
sphere of action that sets up movement, and not any 
and every good ; for it sets up movement only in so 
far as it is the motive of something else or the end 
of something which has something else as its object. 
And we must lay down the principle that the apparent 
good can take the place of a real good, and so can the 
pleasant, for it is an apparent good. So that it is 
clear that in one respect that which is eternally 
moved by the eternal mover, and the individual 
animal, are moved in a similar manner, but that in 
another respect they are moved differently ; and so 5 
while other things move eternally, animal movement 
has a limit. Now the eternally beautiful and that 
which is truly and primarily good, and not at one 
moment good and at another not good, is too divine 
and precious to have anything prior to it. 

The prime mover, then, moves without itself being 
moved, but desire and the desiderative faculty set 
up movement while being themselves moved. But 
it is not necessary that the last of a series of things 
which are moved should move anything ; and from 
this it is clear that it is only reasonable that pro- 



rj (popa TeAevrcLLCL rcov yivopbevaiv ev rots kivov- 
[livens 1 • KcveTrai yap Kal iropeveTai to ^wov ope^et 

5 r] irpoaipeveiy aXXoicodevrog rtvos Kara, tt)v ai- 
aOrjcuv 77 tt\v (fyavraGLOLV. 

VII. Uqjs he voqjv ore fiev 7Tpdrr€L ore §* ou 
TTpdrreiy Kal Kcvelrou, ore §' ov Kivelrai; eoiKe 
TTapaTrArjaltos ovpifiaiveiv Kal nepl rcov aKivqTiov 
Stavoovfievois Kal avXAoyi^opevois . aAA' eKel fiev 

10 OecoprjfjLa to reXog (orav yap rds hvo irpoTacrecs 
vor\Gr\> to ovynrepaopLa evor\ue koX avveOrjKev) , 
IvravOa 8' eK tcLv Bvo TrpoTauetov to crvpLTrepaofia 
yiverat r) 7rpat;i$, olov orav vor\ur\ otl rravrl fia- 
hioriov di'dpajTTcp, avrog S* dvOpcoTros, ^aSt^ec 
evOews, av 8' ore ovhevl fiahiariov vvv dvBpamoi, 

is avTog S' dvBpcoiTOs, evdvs r)pepel' Kal ravra dpLcfxx) 
Trpdrrei, dv pr) ti kqjXvj] rj dvayKa^jj. iroiryriov 
fiot dyaBoVy 01/aa 8' dyaOov TTOiel otKiav evQvs. 
GK€irdapLaTOs oeofiac, Ifidriov Se GKenaapia* [fiartov 
Seopbat. ov Seofiac, -noirfreov* Ipbarlov heopiac 

20 If-ldriOV 7TOLK)T€OV. Kal TO CrVpL7T€paGpLa, TO LpidTLOV 

7TOir}T€ov y rrpd^is eGTLv. irpaTTec 8' drf dp)(fj$. 
el IfiaTLOv ecTaiy dvdyKTj ToSe rrpajTOVy el he ToSe, 
ToSe' Kal tovto rrpaTTei evOvg. otl pev ovv rj 
TTpd^ts to crvpLTrepacrpLay cfyavepov at Be TrpoTaaeis 
at TTOLrjTLKal Sid Bvo ei$a>v yivovrai, Sta Te tov 
25 dyadov Kal 8ta tov hvvaTov. 

v Q.u7rep Se tqjv epojTcLvTajv evioiy ovtw ttjv eTepav 

1 KivovpLtvois Jaeger : yiyvo/juEvois libri. 

i.e. the objects of science ; cf. An. Post. 71 b 18 ff. 



gression should be the last thing to happen in things 
that are moved, since the animal is moved and walks 
from desire or purpose, when some alteration has been 
caused as the result of sensation or imagination. 

VII. But why is it that thought sometimes results 
in action and sometimes does not, sometimes in 
movement and sometimes not ? Apparently the 
same kind of thing happens as when one thinks and 
forms an inference about immovable objects. But 
in the latter case, the end is speculation (for when you 
have conceived the two premisses, you immediately 
conceive and infer the conclusion) ; but in the former 
case the conclusion drawn from the two premisses 
becomes the action. For example, when you conceive 
that every man ought to walk and you yourself are a 
man, you immediately walk ; or if you conceive that 
on a particular occasion no man ought to walk, and 
you yourself are a man, you immediately remain at 
rest. In both instances action follows unless there is 
some hindrance or compulsion. Again, I ought to 
create a good, and a house is a good, I immediately 
create a house. Again, I need a covering, and a 
cloak is a covering, I need a cloak. What I need I 
ought to make ; I need a cloak, I ought to make 
a cloak. And the conclusion " I ought to make a 
cloak " is an action. The action results from the 
beginning of the train of thought. If there is to be 
a cloak, such and such a thing is necessary, if this 
thing then something else ; and one immediately 
acts accordingly. That the action is the conclusion is 
quite clear ; but the premisses which lead to the doing 
of something are of two kinds, through the good and 
through the possible. 

And as those sometimes do who are eliciting con- 



TTporaaiv T7]v hrjX-qv ov& rj Stdvoca e^tcrracra gkott€1 
ovoev olov el to fiaol^eiv ayaOov dvOpajiroj , otl 
avros avQptoTTos , ovk eVSicrrpi/^a. Sto Kal b'oa fir) 
XoyiadfJievoL 7TpaTTO[kev 3 ra^u TTpaTTOfiev. orav yap 
ivepyrjorj r) rfj aio9r)oei irpos to ov ev€Ka rj rfj 
30 (jxivraaLa r) tw i'Wj ov opiyeraiy evdvs rroiel' oW 
ipwr-qaews ydp r) vorjoecos r) rrjs ope^eojs yiverai iv- 
epyeia. ttoteov jjloi, rj e7Ti9vfila Aeyer ToSt Se 770T0V, 
r) alaQ-qGis elirev r) r) <f>avTaola rj 6 vovs* ev6vg irivei. 


£a>a opfiajcri, rrjs fiev iox^ rr l s curias rod KiveloQai 
35 ope^ecos ovaiqs, ravrrjs Se yivofieinrjg r] St* alcrOrjO'ecDS 
rj bid (fxxvraoias Kal vorjaewg. tcov S' opeyofievujv 
TTpdrretv rd fxev oY eTTidv\ilav r) Ovfidv rd Se St' 
701 b ope^iv r) fiovArjaiv rd fiev ttoiovgi, rd he Trpdrrovoiv. 
"Qajrep oe rd avrdfiara Kiveirai jiLKpas Kivrjcreajs 
yivofJLevrjs, Xvofievcov tcov arpefiAajv Kal Kpovovowv 1 
dAAryAas 1 [rds arpefiAas], 2 Kal to dfid^iov, oirep 
5 {to) 3 oxovfievov avTo Kivei els evOv, Kal irdXcv 
kvkXw KtveiTai Tip avLaovs ^X €LV r °vs Tpoxovs 
(o yap eAaTTCov coawep KevTpov ytWrat, KaOdrrep 
ev rot? KvAwSpois) j ovtoj Kal to, £cua /antral. 
k'xei yap opyava Tota{3ra Tr\v t€ tcov vevpcov 
<f>VGiv Kal Tr)v tcov octtlov, Ta fiev cos eK€L to. 

1 xpovovawv scripsi (Leon, renders laxatis seque mutuo im- 
pellentibus vertebris) : KpovbvTuv libri. 

3 ras <rrp^\as seclusi. 3 t6 addidi. 

a For this technical use of ipcorav cf. An. Prior. 24 a 24. 

b By the removal of the pegs (£tf\a), cf. below, 701 b 9, 10. 

c The context seems to show that the toj^-carriage was 
on an axle which coupled two wheels of unequal diameter. 
There is, however, no evidence for the existence of such toy- 
carriages in antiquity. 


elusions by questioning,* 1 so here the mind does not 
stop and consider at all one of the two premisses, 
namely, the obvious one ; for example, if walking is 
good for a man, one does not waste time over the pre- 
miss " I am myself a man." Hence such things as we 
do without calculation, we do quickly. For when a 
man acts for the object which he has in view from 
either perception or imagination or thought, he 
immediately does what he desires ; the carrying out 
of his desire takes the place of inquiry or thought. 
My appetite says, I must drink ; this is drink, says 
sensation or imagination or thought, and one 
immediately drinks. It is in this manner that animals 
are impelled to move and act, the final cause of their 
movement being desire ; and this comes into being 
through either sensation or imagination and thought. 
And things which desire to act, at one time create 
something, and at another act, by reason either of 
appetite or of passion, or else through desire or wish. 

The movement of animals resembles that of 
marionettes which move as the result of a small 
movement, when the strings are released & and strike 
one another ; or a toy-carriage which the child that 
is riding upon it himself sets in motion in a straight 
direction, and which afterwards moves in a circle 
because its wheels are unequal, for the smaller wheel 
acts as a centre, c as happens also in the cylinders. d 
Animals have similar parts in their organs, namely, 
the growth of their sinews and bones, the latter cor- 
responding to the pegs in the marionettes and the 

d The marionettes seem to have been worked by means of 
cylinders round which weighted strings were wound, the 
cylinders being set in motion by the removal of pegs. 



£vXa Kal 6 GiSrjpcSy ra 8e vevpa <hs al arpe^Xar 
10 a>v Xvofxevcov Kal dvLefievcov kivovvtgli. iv fiev 
ovv tols avTOfidrois Kal rot? djia^lois ovk Hotlv 

dXXoLWOLS, €7766 €L iyLVOVTO iXaTTOVS 01 ivTO$ 

rpoxol Kal ttoXiv fAei^ovs, kolv kvkXu) to avro 
€kli'€lto' iv hi raj £wa) ovvaTai TO avTo Kal 
pLel^ov Kal eXa-Tov yLveoQai Kal tcl cr^/xara ^tera- 

15 jidXXeiv, av^avoj-ievtDV tcov fiopcwv Sia. depfioTTjTa 
Kal ttclXlv ovGTeXAofjLevajv Sta ipv£iv Kal dXXoLov- 
fievcov. olXXolovol 8' at <j>avTaulai Kal al aloO-qoeis 
Kal al evvoiai. al fiiv yap aloQ-qaeis evQvg vtt- 
apypvoiv aXXoLcoaeis tlv€$ oucrai, rj 8e <j>avTaGia Kai 
r) v6rjGt£ TTjV tcov it pay[x6.T<j}v eyovGi ovvapuv Tpo- 

20 ttov yap Tiva to etSo? to voovfievov to tov Oeppiov 
rj tpvxpov rj rjoeos r] (f>of3epov tolovtov Tvyyjxvti 

OV OLOV 7T<£p Kal TCOV TTpayjiaTCOV €KaGTOV } Sio Kal 
(f>pLTTOVGL Kal <j)ofioVVTai VOTjGaVT€£ fJLOVOV . TdUTa 

8e udvTa irddi] Kal dXXotcoaeLs elolv. dXXotov- 
piivcov 8' iv to) GcLfxaTi ra jiiv [xel^co ra 8* iXaTTto 

25 ytVerat. on 8e jiiKpd (jL€TafioXr) yivofxivrj iv dpxfj 
fxeydXas Kal 77oAAa? ttolcl Sia^opa? arrodev, ovk 
aSrjXov otov tov olaKos aKapialov tl fieOiGTafiivov 
TToXXrj r) Trjs -rrpcbpas ylveTai ^eracrraats'. en 8e 
Kara OepfjLOTrjTa rj ipv^iv r) /car' dXXo tl tolovtov 
TtdOos oTav yivrjTaL dXAoLCUOLs Trepl Trjv Kaphlav, 

30 Kal iv Tavrvj /caret fiiyeOos iv dvaLoOrjTO) fiopLcp, 
TToXXrjv 7tol€l tov CTcofxaTOS oiatftopdv ipvOrjfjLacn 

Kal OJXpOTTjGL Kal (f)pLKaL$ Kal TpOflOLS Kal TOLS 

VIII. 'Apxr) fxev ovv, tooTTzp etprjTai, Trjs 

° The reference is probably to some part of the toy- 



iron, a while the sinews correspond to the strings, the 
setting free and loosening of which causes the move- 
ment. In the marionettes and the toy-carriages no 
alteration takes place, though, if the inner wheels 
were to become smaller and then again larger, the 
same circular movement would take place. In the 
animal, however, the same part can become both 
greater and smaller and change its form, the mem- 
bers increasing through heat and contracting again 
through cold and thus altering. Alteration is 
caused by imagination and sensations and thoughts. 
For sensations are from the first a kind of altera- 
tion, and imagination and thought have the effect 
of the objects which they present ; for in a way the 
idea conceived — of hot or cold or pleasant or terrible— 
is really of the same kind as an object possessing one 
of these qualities, and so we shudder and feel fear 
simply by conceiving an idea ; and all these affec- 
tions are alterations, and when an alteration takes 
place in the body some parts become larger, others 
smaller. Now it is clear that a small change taking 
place in an origin of movement 6 causes great and 
numerous changes at a distance ; just as, if the rudder 
of a boat is moved to an infinitesimal extent, the 
change resulting in the position of the bows is con- 
siderable. Furthermore, when, owing to heat or 
cold or a similar affection, an alteration is caused 
in the region of the heart — and even in an imper- 
ceptibly small part of it — it gives rise to a consider- 
able change in the body, causing blushing or pallor 
or shuddering or trembling or the opposites of these. 
VIII. The origin, then, of movement, as has already 

b i.e. here, the heart, cf. below, 701 b 30 ; see also note on 
698 bl. 



701b , , , ^ s , , , 

KLvrjaetos to ev toj irpaKTcp olcoktov /cat <p€VKTOV 

i£ dvdyKTjs S' oLKoXovdel rfj vorjcrei Kal rfj <^avracrta 
35 avrcjv OepfjLOT-qs Kal ipv^is . to jxkv yap Xv7T7]p6v 
(frevKTOP, to S' fjSv Siqjktov (aAAa, XavOdvei 7T€pl 
ra fJLLKpd tovto avjifiaivov), eort Se ra XvTrrjpd 
702 a Kal rjSea ndvTa cr^eSof fieTa ipv^ecos twos /cat 


9dppr) yap Kal cfrofioL Kal a^pooioiao-jiol Kal rdAAa 
ra acjofxaTiKa XvTrrjpd Kal rjSea rd fiev KaTa jxopiov 

fJL€Ta OeppLOTTJTOS T) lpV^€Ci)S icTTL, TO. Se /Ca#' SXoV 

5 to awjia- fjLvrjfjLac Se /cat eA^t'Scs, otoy et'SajAots" 


jitaAAoy atTtat tcDv aura)*' etcrtV. coot' euAoya;? 
77S77 Sr] fjicovpy ecTac tcx eVro? /cat rd 7re/Dt ras" apx&s 
twv opyaviKcjv pLopccov fieTafidXXovTa e'/c Treir^yoTCDV 
10 vypa Kal i£ vypdjp TrzirrfyoTa Kal jitaAa/cd Kal 
GKXrjpa i£ dAA^Aajy. tovtcov Se crvpifiaivoPTajv 

7TOir)TlKOV TOtaVT7]P e^Ol'TaJ^ T V V 4 > V (TLV °^ aV 7T0 ^" 

Aa^ou elprfKapieVy oirorav GvpLpfj cqgt elvai to 
jji€v TroLTjTCKov to Se 7Ta0YjTLK6v f Kal firjSep aTToXtTTTJ 
is avTwv e/cdVeooi' tojv eV Tw Xoyw t evOvs TO jiev 
7tol€l to Se 77acr\;et. Sta touto 8' dfia (Lg €L7T€lv 

VO€L OTt TTOpeVTCOV Kal 7TOp€V€Tai } dv {JLY} TV €[JL~ 

TToSc^rj €T€pov. ra \.L€V yap opyaviKa p<€pri irapa- 
GKevd^ei eVtT^SetoJS ra TrdOrj, rj S' ope^ts tcx 
irdQy] s ttjv S' ope^tv r) <f>avTaoia* avTrj Se ylverai 
r) Sta vorjoeajs rj St' atcr^creajs. dpia Se Kal ra^u 
20 Sta to {to) 1 ttol7]tik6v Kal TraOrjTCKOV twv irpos 
aAAriAa elvai ttjv cfyvcrtv. 

1 to add. Bonitz. 



been said, is the object of pursuit or avoidance in the 
sphere of action, and heat and cold necessarily follow 
the thought and imagination of these objects. For 
what is painful is avoided, and what is pleasant is 
pursued. We do not, it is true, notice the effect of 
this in the minute parts of the body ; but practically 
anything painful or pleasant is accompanied by some 
degree of chilling or heating. This is clear from the 
effects produced. Reckless daring, terrors, sexual 
emotions and the other bodily affections, both pain- 
ful and pleasant, are accompanied by heating or 
chilling, either local or throughout the body. Re- 
collections too and anticipations, employing, as it 
were, the images of such feelings, are to a greater or 
less degree the cause of the same effects. So it is 
with good reason that the inner portions of the body 
and those which are situated near the origins of the 
motion of the organic parts are created as they are, 
changing as they do from solid to liquid and from 
liquid to solid and from soft to hard and vice versa. 
Since, then, these processes occur in this way, and since, 
moreover, the passive and the active principles have 
the nature which we have frequently ascribed to them, 
whenever it so happens that the one is active and the 
other passive and neither fails to fulfil its definition, 
immediately the one acts and the other is acted upon. 
So a man thinks he ought to go, and goes, practically 
at the same time, unless something else hinders him. 
For the affections fittingly prepare the organic parts, 
the desire prepares the affections, and the imagina- 
tion prepares the desire, while the imagination is due 
to thought or sensation. The process is simultaneous 
and quick, because the active and the passive are by 
nature closely interrelated. 


To Se kivovv Trptorov to ^toov dvdyKrj elvai ev tivi 

apXfj' V ^6 KOLfJLTTTj OTl \Xe.V €(JTl TOV }JL€V dpXrj TOV 

Se TeXevTrj s €iprjraL. Sio Kal euri jxev cos evl s eari 
8' u)$ Svcrl xp^ TaL 4 ) ^ Gts a ^ r ??- orav yap KLvijrai 
25 evTevBev, dvdyKrj to (xev rjpepLetv Ttov mj^elajv rtov 
eaxdrtov y to Se Kiveiudai' on yap Trpos rjpepiovv Set 
drrepelSecrOai to kivovv, etprjraL irpoTepov. KtveTraL 
jiev ovv Kal ov Kivel to eo*x arov rod fipa^ovos , rrjs S* 

€V Ttp wXtKpdvU) K.dfJLljj€U)S TO fJL€V KLVeiTat TO €V aVTtp 

to) SXtp KivovjJLevcp, dvdyKrj S* elvai rt Kal aKLvrjrov, 
30 o S77 cj)a{JL€v hvvdjxei jxev ev elvai arjfjLeioVy evepyeia 
oe ylvecrdat ovo' coot el to L^toov rjv ftpayiwv, zv- 
ravS* dv ttov rjv rj dpxrj rfjs 4 fV XV^ V xwovaa. 
err el S' iv8ix €TaL Kal Trpos rrjv x € ^P a ^X €LV TL 
ovrtos Ttov difjvxco^y olov el klvoltj Trjv ftaKrrjplav 
ev Tjj X €t P^> ^CLvepov oti ovk dv eirj iv ovSeTepto 
35 r) ipvxr) Ttov €GxdTO)v 3 out' iv Tip eaxdrto tov 
KLvovfievov our' ev rfj erepa dpxfj- Kal yap to 
702 b t;vXov k'xei Kal dpxrjv Kal TeXos Trpos rrjv x € W a - 
toare Sta ye tovto 3 el jxrj ev tjj fiaKTrjpla rj Kivovcra 
diro ttjs ipvxrjs dpx^J eveuTiv, ovV ev rfj X €L P^' 
ojioltos yap exei Kal to aKpov Trjs x €l P°$ Trpos tov 
Kaprrov, Kal tovto to jxepos Trpos to toXeKpavov. 
5 ovt)ev yap hiatf>ipei rd Trpocrrre^vKOTa Ttov jxrj 

i.e. the same relation as the forearm has to the elbow. 

b i.e. the end of the stick where it meets the hand. 

c i.e. the origin of the movement of the hand which is 
situated in the wrist. 

d It is impossible to find a word in English which covers 
the double meaning given to dpxv here and in the previous line 
(see note on 698 b 1). The sentence kcll yap to ^v\ov . . . x € 'P a 
explains why the dpxv Ktvri<rew of the hand is called 7? ertpa 
apxrji viz. that there is another txpxh (in the sense of " be- 
ginning **) in the stick, namely, the point nearest the hand. 


Now that which first causes movement in the 
animal must be situated in a definite beginning. 
Now it has already been stated that the joint is the 
beginning of one thing and the end of another ; where- 
fore nature employs it sometimes as one and some- 
times as two. For when movement is being origin- 
ated from it, one of its extreme points must be at 
rest, while the other must move ; for we have already 
said that what causes movement must be supported 
on something which is at rest. The extremity, there- 
fore, of the forearm is moved and does not cause 
movement, but in the elbow-joint one part, namely 
that which is situated in the actual whole which is in 
motion, is moved, but there must also be something 
which is unmoved ; and this is what we mean when 
we say that a point is potentially one but becomes 
actually two. So if the forearm were a living creature, 
it is somewhere near this point that the origin of move- 
ment set in motion by the soul would be situated. 
Since, however, it is possible for an inanimate object 
to bear this same relation to the hand, a for instance 
if one moves a stick in one's hand, it is clear that the 
soul could not be situated in either of the extremities, 
neither in the extremity of that which is moved 6 nor 
in the other origin of movement (p-pxv) c '•> f° r the stick 
has an end and a beginning (a/>x^) d in relation to the 
hand. So, for this reason, if the origin of movement 
set up by the soul is not situated in the stick, it is not 
situated in the hand either ; for the extremity of the 
hand e bears the same relation to the wrist as the 
latter does to the elbow. For there is no difference 
between what is attached by growth and what is not 

• i.e. the point where the hand joins the stick. 



ylveTai yap wGirep dtfyaiperov fiepos rj jSa/cT^pia. 
avdyKYj dpa iv /x^Se/xta etvai dpxfj, V €<jtiv d'XXov 
TeXevTr), prjSe. ei n iarlv eTepov iKeivov i^WTepw, 
otov tov [lev rrjs fiaKTrjplas iox^Tov iv rfj X € ¥^ 
rj dpx^jj tovtov 8' iv Kapirw. el Si /xt^S' iv rfj 
10 X €L P^> ° TL dvwTepw e.Ti 3 r) dpx?) ouS' ivravBa* en 
yap tov wXeKpdvov pcevovTos Kiveirai dirav to 
Kara) owexes. 

IX. *E77€t §' OpuOLOJS €^€t 0,770 TWV dpiOTepWV 

Kal diro rwv oe^iwv, Kal dfia rdvavrla Kivelrai, 
ware per) etvat tw rjpepeiv to $e£iov KivelaOat to 
dptarepov pLrj& av tw tovto iKeZvo, del §' iv rw 

J5 dvwrepw dpL<f)OTepwv rj dpxr] y dvdyKT) iv tw /xecrcu 
etvat ttjv dpxrjv tt)s fax^s t V s kwovgtjs' dpccfyoTepwv 
yap twv aKpwv to fiecrov eax^Tov. opioiws §' e^€t 
rrpos Tas Kwrjoecs tovto Kal Tas diro tov avw Kal 
KaTWj otov Tas diro rrjs Kecf>aXrjs Kal 1 rds drro Trjs 

20 pdxews tols exovoi pa^w. Kal evXoyws Se touto 
avpLfiefirjKev Kal yap to aladrjTiKov ivTavOa etval 
<f>apev y wot aXXoiovpievov Sid ttjv aiud-qoiv tov 
tottov tov rrepl ttjv apxyv f<al pieTafidXXovTOS rd 
eXopceva avpLpceTapaXXet iKTewopcevd tc Kal awayo- 
pueva ra popia, wgt* it; dvdyKrjs hid ravTa ylveodai 


1 Kal scripsi : irpbs libri. 

This is simply a restatement of the doctrine of 702 b 1-4. 
The true dpxv is not situated in the extremity of the stick 
nearest to the hand (which is an dpxv as being the place 
where the stick begins in relation to the hand), nor yet in any 
other member, such as the wrist, which is still farther away 
from the stick and is an apxy a s being the origin of motion 
in the hand. The wrist, elbow, and shoulder are all of them 


so attached ; for the stick becomes a kind of detached 
member. The origin of movement, therefore, cannot 
be situated in any origin which is the termination of 
something else, nor in any other part which is farther 
from it ; for example, the origin of movement of the 
extremity of the stick is in the hand, but the origin 
of the movement of the hand is in the wrist. a And 
so if the origin of movement is not in the hand, be- 
cause it is still higher up, & neither is it in this higher 
position ; for, again, if the elbow is at rest, the con- 
tinuous part below it can be set in motion as a whole. 

IX. Now since there is similarity in the left and the 
right sides of the body, and the opposite parts can be 
moved simultaneously, so that it is impossible for the 
right side to move just because the left is at rest or vice 
versa, and the origin of movement must be in that 
which lies above both sides, it necessarily follows that 
the origin of movement in the moving soul must be 
between them ; for the middle is the limit of both 
extremes. And it stands in the same relation to the 
movements above as to those below, to those, for 
example, which proceed from the head and to those 
which proceed from the spine in animals which have 
a spine. And there is good reason for this ; for we 
say that the organ of sensation is also situated in 
the centre of the body ; and so if the region round 
about the origin of movement is altered by sense- 
perception and undergoes change, the parts which 
are attached to it change with it by extension or con- 
traction, so that in this way movement necessarily 
takes place in animals. And the central part of the 

dpx a ^ i n relation to the parts below them, but the true apxh 
is situated in the soul, which lies in the centre of the body. 
6 i.e. the wrist. 



702 5 / \ ft 5 » 

pcepos hwdfiec pcev ev } evepyeta S dvdyKTj yiveaOai 
TrXecco' Kal yap dpca Kiveirai rd KwXa drrd rrjg 
apxys, Kal Oarepov rjpefiovvros Oarepov Kiveirai, 
Xeyco S' otov enl rrjs ABT to B KLvelrai, Kivel 
he to A. aAAa firjv het ye ri r\pe\ieLV 3 el fieXXei 

80 to pcev KiveioQai to he Ktvelv. ev dpa hvvd\iei ov 
to A evepyeia hvo ecrrai, ixyur dvdyKrj firj uriypur)v 
dXXa pieyeOos tl etvac. dXXa firjv eVSe^eTCU to T 
dpca rat B KLvelaOaij uxjt dvdyKY) dfX(f)orepa£ raj 
dpxds rag ev rw A Ktvovfievag KiveZv. Sec ri dpa 
elvai irapd ravras erepov to klvovv Kal pcrj klvov- 

35 pcevov. direpeihoLVTO [xev yap dv rd aKpa Kal at 
apx^l at ev rep A 7rpds aAA^Aas" Kivovfievtov, wcnrep 

703 a av el rives rd vwra avrepethovres Kivoiev to, crKeXr]. 

dXXa to klvovv a/x</>a> dvayKatov elvai. rovro 8* 
icrrlv rj ip v X 1 l> ^ T ^P ov ovaa rod fieyeOovg rod 
tolovtov s ev rovrcp o° ovaa, 

X. KaTa [lev ovv rov Aoyoy rdv Xeyovra rrjv 

5 alrtav rrjs KLvrjuews icrrlv rj ope^is rd pLecrov, o 
Kivei KLVOvfievov ev he rots epupvxoLS awpiaaL Set 
Tt elvai crajpLa roiovrov. to puev ovv Kivovfxevov 
fiev iiT] 7re(j)VK0s he Kiveiv Svvarai rtd<3x €iV Kar 
dXXorpiav hvvapuv rd he klvovv dvayKatov k'xeiv 
rtvd hvvafiLV Kal Icrxvv. irdvra he ^alverai rd 

10 £<5a Kal k'xovra nvev\xa GV{i<f>vrov Kal laxvovra 
rovrcp. (tl$ fiev ovv r) acorrjpLa rov crvpi(j)vrov 
TTvevpLaros, eLprjrai iv aAAotS".) rovro he TTpds 
rr)v dpxrjv rrjv ipvx^KTjv eoiKev opcolcog e'xetv warrep 
a See Introd. p. 436. 



body is potentially one, but actually must necessarily 
become more than one ; for the limbs are set in 
motion simultaneously from the origin of movement, 
and when one is at rest the other is in motion. For 
example, in ABC, B is moved and A moves it ; there 
must, however, be something at rest 
if one thing is to be moved and 
another is to move it. So A, though 
potentially one, will be actually two, 
so that it must be not a point but a 
magnitude. Again, C may be moved 
simultaneously with B, so that both 
the origins in A must cause movement by being 
moved ; there must, therefore, be something other 
than these origins which causes movement without 
being itself moved. Otherwise, when movement took 
place, the extremities, or origins, in A would rest 
upon one another, like men standing back to back and 
moving their limbs. There must be something which 
moves them both, namely the soul, other than such 
a magnitude as we have described but situated in it. 

X. In accordance with the definition which defines 
the cause of motion, desire is the central origin, which 
moves by being itself moved ; but in animate bodies 
there must be some bodily substance which has these 
characteristics. That, then, which is moved but does 
not possess the natural quality of setting up move- 
ment may be affected by a power external to it, and 
that which causes movement must possess some 
power and strength. Now all animals clearly both 
possess an innate spirit and exercise their strength 
in virtue of it. (What it is that conserves the innate 
spirit has been explained elsewhere. ) This spirit 
seems to bear the same relation to the origin in the 



to ey rat? Kaynrais u-qpieiov, to kivovv koli kivov- 

fJL€VOV, TTpOS TO aKLVTjTOV . €7T€l S* 7] OLpXV T0 ^ 

/xe> ev Tfj KapSla tols S' iv rep ai^aAoyov, Std tovto 
Kal to irvevpia to ovfufivTOV evTavQa (^atVerat ov. 

15 TTOTepOV fl€V OVV TdVTOV e<7Tt TO TTVeVfJLd del TJ 

ytVerat del eTepov, eoTto d'Xkos Xoyos (6 avTOS 
yap euTi Kal irepl twv dXXwv pLopiajv)- (^atVerat §' 
evcj>va>g eypv Trpos to kivt)tik6v elvai Kal irapeyeiv 
layyv. ra S' epya Trjs Kivrjaeajs coats' Kal eA^t?, 

20 waTe Set to b'pyavov av^dveaOai Te Svvaudac Kal 
crvoTeXAeaO 'at. TOiavTf] S' Iotiv rj tov rrvevftaTOS 
envois' Kal yap dfiiaoTos ovaTeXXofievr), Kal 
fiiaGTiKr) Kal cootiky) 8td ttjv avrqv aiTiav, Kal 
e'^et Kal fiapos vrpos Ta nvpwSrj Kal Kov<f>oT7]Ta 
npos Ta evavTia. Set Se to fieXXov Kivelv per) 

25 dAAoiajaet tolovtov etVar /cparet yap /card ttjv 
V7repox^}v Ta <f)vaiKa aaj/xara dAA^Acov, to pcev 
Kovcf)ov KaTOJ V7t6 tov fiapvTepov dTroviKwfievov, 
to he fiapv dvo) vtto tov Kov<f>OTepov. 

'Qi [iev ovv Kivel Kivov\xevuy pLoplw r) i/jvxrjteiprjTaiy 
Kal St' r)v air Lav* V7roXr)7TT€ov Se ovveuTavai to 

30 l,a)ov woirep ttoXlv evvo[iov\xevr]V \ ev Te yap Tfj rroXec 
OTav dirat; Gvcrrfj 1 r) rd^t?, ovSev Set Kexajpicrfievov 
fjLOvdpxov, ov Set uapelvai Trap* eKaaTOV twv 
yivofievajv, dAA' avTos eKauTOS Troiel Ta aVTov 
d)£ TeTaKTai, Kal ylveTai rdSe jiterd roSe Std 

1 crvarfi P : arfj ES Y. 

a For this meaning of d^laaros cf. Plato, 7777?. 61 a. The 
action of the wvevfxa is represented as resembling that of the 
breath in the lungs ; when the breath contracts it lacks force 
and the lungs collapse, when it expands it thrusts outwards 
and exercises force. 

b Namely, expansion. 


soul as the point in the joints, which moves and is 
moved, bears to that which is unmoved. Now since 
the origin is in some animals situated in the heart, in 
others in what corresponds to the heart, it is therefore 
clear that the innate spirit also is situated there. 
Whether the spirit is always the same or is always 
changing must be discussed elsewhere (for the same 
question arises about the other parts of the body) ; 
at any rate it is clearly well adapted by nature to be 
a motive power and to exercise strength. Now the 
functions of movement are thrusting and pulling, so 
that the organ of movement must be able to increase 
and contract. And the nature of spirit has these 
qualities ; for when it contracts it is without force," 
and one and the same cause 6 gives it force and en- 
ables it to thrust, and it possesses weight as compared 
with the fiery element, and lightness as compared 
with the contrary elements. Now that which is to 
create movement without causing alteration must be 
of this kind ; for the natural bodies d overcome one 
another according as one of them prevails, the light 
being conquered and borne down by the heavier and 
the heavy borne up by the lighter. 

We have now stated what is the part by the move- 
ment of which the soul creates movement and for 
what reason. The constitution of an animal must be 
regarded as resembling that of a well-governed city- 
state. For when order is once established in a city 
there is no need of a special ruler with arbitrary 
powers to be present at every activity, but each indi- 
vidual performs his own task as he is ordered, and one 
act succeeds another because of custom. And in the 

e The contrary of fire is water, cf. Be gen. et corrupt. 331 a 1 . 
d i.e. the elements. 

Q 475 



35 <f)vcriv ylverai Kal rw ir€<j>VK€vai eKaarov ovrco 
ovardvrwv noieiv to avrov epyov s were firjSev 
Setv iv eKaarw etvat tfiv)(i]v s dXX 3 ev nvt apxfj T °v 
703 b atbjJLOLTOs ovarjs raXXa £rjv fiev rw 7TpoGTrecj>VKevai, 
noi€lv he to epyov to avrwv Sea tt)v <j)vaw. 

XI. Tlws fiev ovv Kivelrai rds eKovatas Kivrjcreis 
rd t ) wa s Kal Sia rivets air lag , eiprjrai' Kivelrai Se 

5 rivas Kal olkovctIovs evta rwv pLepwv, rag Se 
vXelarag ovx eKovalovs. Xeyw 8' aKovulovs fiev 
otov rrjv rrjs KapSlag re Kal rrjv rod alSolov (rroXAdKis 
ydp <f>avevros nvos s ov fievroi KeXevcravros tov 
vov KLVovvrat) s oi)^ eKovalovs 8* ofov vttvov Kal 
iyprjyopoiv Kal avaTrvorjV, Kal Seat dXXat roiavral 

10 elcnv. ovOevos ydp rovrwv Kvpla drrXw? earlv 
ovu rj (pavraata ovu rj opef is*, aAA eireibrj avayKt] 
aXXoiovudai rd l,wa <j)VGiK7)v aXXolwaiv, dXXoiov- 
fievwv Se rwv fioplwv rd fiev av^eorOat rd Se <$)6lveiv s 
war 7]8rj KiveluOai Kal jjLerafidXXeiv rds 7T€(f>VKvlas 
execrSai pLerafioXds dXXrjXwv [alrlai Se rwv 

15 KLv-qaeojv OepjjLorrjres re Kal ipv^ecs, ai re OvpaQev 
Kal ai evros virdpypvaai fyvviKal), Kal ai rrapd 
rov Xoyov Srj ycvofievai Kiviqoeis rwv prjdevrwv 
fiopLwv dXAoiworews avfnreaovorrjs ylvovrai. rj ydp 
vorjaLs Kal rj <f>avraorla J wurrep eiprjrai Trp6repov } rd 
TToaqriKa rwv iradrjfjLarwv npoac^epovaLV rd ydp 61877 


fiopiwv ravra Troiel emSrjXws Sid to worrrep ^wov 
Keywpiopievov eKarepov elvai rwv fiopiwv [• rovrov 

a See note on 698 b 1. 
b Viz. the heart and the privy member. 
c 701 b 18 ff. 



animals the same process goes on because of nature, 
and because each part of them, since they are so 
constituted, is naturally suited to perform its own 
function ; so that there is no need of soul in each 
part, but since it is situated in a central origin of 
authority over the body, a the other parts live by 
their structural attachment to it and perform their 
own functions in the course of nature. 

XI. We have now discussed the manner of the 
voluntary movements of animals, and the cause of 
them. Some of their parts, however, undergo certain 
involuntary movements, though most of these are 
really non-voluntary. By involuntary I mean such 
movements as those of the heart and of the privy 
member, which are often moved by the presentation 
of some image and not at the bidding of reason. By 
non-voluntary I mean sleeping and waking and respira- 
tion and the like. For neither imagination nor desire 
is strictly speaking responsible for any of these move- 
ments ; but, since animals must necessarily undergo 
physical alteration, and, when their parts undergo 
alteration, some increase and others decrease, and so 
their bodies immediately move and undergo the 
natural sequence of changes (the causes of their 
movements being the natural heatings and chillings, 
both external and internal), the movements too of 
the above-mentioned parts b which occur contrary to 
reason are due to the occurrence of a change. For 
thought and imagination, as has already been said, c 
induce the states which cause the affections ; for 
they present the images of the things which cause 
them. Now these parts act in this way much more 
conspicuously than any others, because each is as it 
were a separate vital organism[, the reason being that 



S' aiTLOv otl exovarw vyporrjra ^WTwqv]. 1 rj fiev ovv 
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25 TOLOVTOV €GTl } Cr7}fl€lOV KOLL yap e*f e'o^eTtU i£ 

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Kal TTpog aAA^Aas ovrcos a<f)LKvovvraL. Set yap 
vofjaat to A apx^* at ovv Kivrjaets Ka9* eKacrrov 
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B apx^] €77 1 to B, rj Se tov T e*77t to T, 77 S' apL<j>olv 
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35 B eVt to A iXOelv d>s eV apx^, oltto Se tou A eVt 
to r co? (177* apxys- ° Tl oTe ftey TauTa 4 vorjadv- 
tojv ytverai r) KLvrjais rj Trapd tov Xoyov iv Tot? 

704 a jxopLOiSy 6t€ S* ov , "alVtov to oVe ^,ev VTrapx^w tt)v 
TradrjTiKTjv vXrjv ore Se ^17 to GavTtjv rj TOiavTrjv. 
Ilept ^teV ow tcoi^ {xoplcav eKaoTov twv ^cLojv, 

704 b /cat 77ept ipvxrjs, €Tt Se 77ept alaOrjcreaJS Kal vttvov 
Kal fjLvrjfJL7)s Kal tt}s Koivrjs Kivrjcrews, €Lpr}Kafi€V 
tols atTtas" Aot77oy Se Trept yeveaeajs etVety. 

1 tovtov . . . {tariKTiv ut interpolamentum del. Jaeger. 
2 yap om. EY. 
3 to? EP : t$ Y : to S. 
4 rairra Jaeger : ra avra P : ravra ES Y, 

• These words are probably an interpolated gloss ; they 



each contains vital moisture]. The reason for this as 
regards the heart is plain, for it contains the origins 
of the senses. That the generative organ is of the 
same nature is shown by the fact that the seminal 
force comes forth from it, being as it were a living 
thing. Now it is only in accordance with reason that 
movements are set up both in the central origin by 
the parts and in the parts by the central origin, 
and thus reach one another. Let A be the central 
origin ; the movements at each letter in the diagram 
drawn above & reach the central origin, and from the 
central origin, when it is moved or undergoes change 
(for it is potentially many), the origin of movement 
in B goes to B, and the origin of movement is C to C, 
and of both to both ; but from B to C it travels by 
going from B to A as to a central origin, and from 
A to C as from a central origin. Movement, however, 
contrary to reason, sometimes takes place and some- 
times does not take place in the organs as the result 
of the same thoughts, the reason being that the 
matter which is liable to be affected is sometimes 
present and sometimes not present in the proper 
quantity and quality. 

We have now dealt with the reasons for the parts 
of each animal, the soul, and also sense-perception, 
sleep, memory, and general movement. It remains 
to deal with the generation of animals. 

are unnecessary in view of the following sentences and con- 
tradictory in doctrine to them. 
6 See figure on p. 473. 



Chap. L Introduction. Problems which arise about 
animal locomotion. Different number of limbs and 
different modes of bending them found in different animals. 

II. Assumption of generally-accepted principles and 

III. Animal movement requires (1) a resisting surface 
against which the limbs can press, (2) a distinction of 
active and passive parts in the animal. 

IV. The dimensions of living bodies. Superior and 
inferior determined by function and not by position. 
Plants and animals compared. Distinction of front and 
back, right and left. The right, as the source of move- 
ment, superior to the left. Man the most highly differen- 
tiated of the animals. 

V. Bipeds, quadrupeds, polypods and footless animals 
distinguished. Quadrupeds inferior to bipeds. Man the 
highest form of biped, being the most " natural." 

VI. All movement in the animal must originate in a 
common centre, equidistant from the centres of movement 
in the limbs. 

VII. Red-blooded animals move at four points : such 
animals are a continuous whole, while bloodless animals 
and polypods are composed of a number of separate 
entities. Even limbless red-blooded animals move at 
four points. 

VIII. Reason for the absence of limbs in snakes. Limbs 
necessarily even in number. 

IX. Flexion necessary to movement, even in limbless 
animals. Its mechanism explained. Illustrations from 
leaping, flying, and swimming animals. 

X. Movement of birds. Use of the tail to guide flight, 


XI. Man, the only erect animal, compared with the 
birds. Winged human beings an impossible invention of 
the artists. 

XII. Differences of flexion in the limbs of man and of 
the quadrupeds explained. 

XIII. The different modes of flexion enumerated and 
illustrated by diagrams. 

XIV. " Diagonal " movement of the legs of quadrupeds. 
Movement of crabs. 

XV. Birds and quadrupeds compared. The structure 
of the legs of birds. Oblique attachment of wings and 
fins. The structure of oviparous quadrupeds. 

XVI. Movement of bloodless animals. The peculiar 
movement of the crab. 

XVII. Crabs, lobsters, flat-fish, and web-footed birds. 

XVIII. Why birds have feet, while fishes have not. 
Fins and wings compared. 

XIX. The movement of testaceans. Conclusion. 


Codex Oxoniensis Collegii Corporis Christi W.A. 
2. 7. 

Codex Vaticanus 260. 

Codex Laurentianus 81. 1. 

Codex Vaticanus 1330. 

Codex Vaticanus 261. 

Latin translation of Nicholas Leonicus. 

Greek commentary of Michael Ephcsius. 

Z = 


Y = 
Leon. = 



a I. Hepl Se rcov ^pTjatftcuv pcoplajv rocs Repots 

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eveKev vrrdpx^i avrocs, in he rrepl rcov hcatbopcov 
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fjLOptois, Kal irpds rd rcov dXXcov rcov rep yevei hta- 

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20 rrjv 7repL(f>€pet,av Kaparrei rd GKeXos, 6 8 opvis 
eirl to KoiXov. Kal 6 dvOpcorros avros avrto 



I. We must next discuss the parts which are useful 
to animals for their movement from place to place, 
and consider why each part is of the nature which 
it is, and why they possess them, and further the 
differences in the various parts of one and the same 
animal and in those of animals of different species 
compared with one another. We must first decide 
what questions we have to discuss. 

One question is, what is the smallest number of 
points at which animals move ; the next is, why red- 
blooded animals move at four points, while bloodless 
animals move at more than four ; and, in general, 
why some animals are without feet, others biped, 
others quadrupeds, and others polypods, and why all 
that have feet at all have an even number of feet ; 
and, in general, why the points at which movement 
is made are even in number. 

We must further consider why a man and a bird are 
bipeds, while fishes are without feet ; and why a man 
and a bird, being both bipeds, have opposite bend- 
ings of the legs. For a man bends his legs in a convex 
direction, a bird in a concave direction ; and a man 



ivavTicos ra aKkXrj Kal tovs fipa^lovas' rovs fikv 
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to epLTTpocrOev Kal to OTTitrQev, rplrr] Se to SeftoV 
Kal to dpicrrepov. irpos Se TOUTOts* on tcov Kivqaecov 
tcov Kara tottov dp^cu coats' Kal eX£is. Kad* 
avTas fJikv ovv avTai, Kara avpifi efijjKos ok Kivel- 

a Le. the front right foot with the left back foot, and the left 
front with the right back. b The Historia Animalium* 

e Leon, renders eodem . . . modo which seems to im- 
ply that he was translating rbv avrbv 2x 0VTa rpdwov. 


himself bends his legs and his arms in opposite 
directions, the arms concavely and the knees con- 
vexly. And viviparous quadrupeds bend their limbs 
in the opposite way to a man's and in opposite 
ways to one another ; for they bend their front legs 
convexly and their back legs concavely. Further, 
quadrupeds which are not viviparous but oviparous 
have the peculiarity of bending their legs sideways. 
A further question is why do quadrupeds move their 
legs diagonally.* 1 

We must examine the reasons of all these and 
similar facts ; that they are facts is clear from our 
Natural History? and we have now to examine their 

II. We must begin our inquiry by assuming the 
principles which we are frequently accustomed to 
employ in natural investigation, namely, by accept- 
ing as true what occurs in accordance with these 
principles c in all the works of nature. One of these 
principles is that nature never creates anything 
without a purpose, but always what is best in view 
of the possibilities allowed by the essence of each 
kind of animal ; therefore, if it is better to do a thing 
in a particular manner, it is also in accordance with 
nature. Further, we must accept the dimensions of 
magnitude in the size and quality in which they are 
present in various objects. For there are six dimen- 
sions grouped in three pairs, the first being the 
superior and the inferior, the second the front and 
the back, and the third the right and the left. We 
must further postulate that the origins of movement 
from place to place are thrusting and pulling. These 
are movements per se ; that which is carried by 



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vov to dvco /cat irpos to vtto tovs Trooas 7rotetTat 
rrjv aXoiv k'xei yap riva dvTepeiaiv 7Tpd$ dXXrjXa 

15 Ta jiopia iv Tat? Kaparatsy /cat oAoj? to ttU^ov 

7Tp6$ TO 7TL€^6fJL€VOV. StO /Cat Ot 7T€VTa0XoL dXXoVTai 

7rXeLOv €xovt€s tovs dATrjpas rj pirj k'xovT€$ y /cat 
ot OiovTes Bottov Biovai irapaaeiovTes Tas ^toas" 
ylvcTat yap tis aTripeLcrts iv Tjj StaTacret npos to,? 
Xetpas 1 /cat tou? Kapirovs. del Be to Kivovpuevov 
20 Suou> eAa^tcrTot? XP^ } 1 X€V0V opyaviKOis fxipeat 

7TOt6tTat T7p fJL€Ta/3oXrjV, TW pi€V d)G7T€paV€L BXlfioVTl, 

ra> Se OXifiopiivcp. to pi€v yap piivov dXlfieTat Bed 

1 Kara /j.4po$ Z : fxipei S : rots fioplois cet. 
2 aurd PUY : aurb S : tauro Z. 

a Special weights (dXr^pes) or sometimes stones were held 
in the hands and thrown backwards by jumpers while in the 
air to add to their impetus ; cf. Norman Gardiner, Greek 


something else is only moved accidentally, for what 
is carried by something else is regarded not as mov- 
ing itself but as being moved by something else. 

III. These points having been decided, let us 
proceed to the considerations which follow from 
them. Of the animals, then, which change their local 
position, some do so with their whole body at the 
same time, for instance those which jump ; others 
move part by part, for example those that walk. 
In both these changes the animal that moves makes 
its change of position by pressing against that which 
is beneath it ; and so, if the latter slips away too 
quickly to allow that which is setting itself in motion 
upon it to press against it, or if it offers no resistance 
at all to that which is moving, the animal cannot move 
itself at all upon it. For that which jumps performs 
that movement by pressing both on its own upper 
part and on that which is beneath its feet ; for the 
parts in a way lean upon one another at their joints, 
and, in general, that which presses leans on that 
which is pressed. Hence athletes jump farther if 
they have the weights in their hands than if they 
have not, a and runners run faster if they swing their 
arms b ; for in the extension of the arms there is a 
kind of leaning upon the hands and wrists. Now that 
which moves always makes its change of place by the 
employment of at least two organic parts, one as it 
were compressing and the other being compressed. 
For the part which remains still is compressed by 

Athletic Sports and Festivals, pp. 298 ff., who proves by 
experiment the truth of the statement made in the present 

b On the importance attached by the Greeks to arm- 
action in running, especially in short races, cf. N. Gardiner, 
op. cit. p. 282. 



705 a , , , , , , -J' 

to (pepetv, to o aipofxevov ret^erai toj cpepovri 

to <f>opTLOv. Sioirep dfiepes ovSev ovtco KiWjOrjvai 

Svvarov ov yap l^et ttjv tov rreLoopievov Kal rod 

25 noirjoovTos iv avro) 1 SidArjifjcv. 

IV. 'E77et 8' elulv al Siaaracret? toj> apidfidv 
e£, at? Spl^eaOaL 7recf>VKe to, £a)a, 2 to re dVa> Kal 
koltcq Kal to epLTrpooOev Kal oiTioQev, €tl Se Se^Lov 
Kal apLGTepov, to fiev avco Kal koltoj jiopiov iravr 
k'xeL ra t^covTa. ov fiovov yap iv tols ^cools earl 
to avco Kal Ko.Ta) } dXXd Kal iv tols </>vtols. Sl- 

80 eLXrj7TTai 8' ^pyep, Kal ov Oioei fiovov Tjj npos T€ 
ttjv yr\v Kal tov ovpavov. oOev fiev ydp rj Trjs Tpocfyijs 
SidSoois Kal r} av^rjois eKaoTOLs, avco tovt iariv 
705 b jTpos o 8' eoxarov avTrj 7iepaiveL ) tovto koltco . 
to fjiiv ydp apxtf tl$ 9 to Se 7repas' dpxr} Se to dvw. 


fiaAXov ovx ojJLolws yap ex €L T fl 9eoeL to dvw Kal 

KaTO) TOVTOLS Kal TOLS ^CpOLS . %X €l Se TTpOS fieV 

6 to oAoy ovx ofJLOLWs, Kara Se to epyov ofiOLCOs. 
al yap pl^aL elal to avco tols cf>vTols' tKeWev yap 
r) Tpocpr) SiaStSoTcu tols tpvofxevoLs, Kal Aap,ftdv€L 
ravTaLS avTr\v s KaOdnep to, £cpa toIs orojiaoiv. 

"Ocra Se firj fiovov £77 dXXd Kal £a>a ion, tols 
toiovtols virdpxei to tc eparpoadev Kal to oiTLoQev. 
10 atadrjaiv yap e\€L TavTa ndvTa, opt^erai Se KaTa 
ravTTjV to Te epurpoaBev Kal to orrLodev* €</>* o 
ixkv yap rj atodrjaLS necpVKe Kal o6ev iarlv eKaaTOLs, 

1 avT$ Jaeger : avr$ libri. 2 fya Y : ffivra ceteri. 

• Cf. above, 704 b 19 ff. b Cf. Be caelo, 294 b 17. 
c More literally "personal." 
d Cf. De vit. long, et brei. 467 b 2 ; Phys. 199 a 28. 



having to carry the weight, and the part which is 
raised is extended by that which carries the weight. 
And so nothing that is without parts can move in 
this manner ; for it does not contain in itself the 
distinction between what is to be passive and what 
is to be active. 

IV. Now the dimensions by which animals are 
naturally bounded are six in number, namely, 
superior and inferior, front and back, and also right 
and left. a Now all living things have a superior and 
an inferior part ; for the superior and the inferior is 
found not only in the animals but also in plants. 6 
The distinction is one of function and not merely of 
position in relation to the earth and heavens. For 
the part from which is derived the distribution of 
nutriment and the growth in any particular thing is 
the superior ; the part to which the growth extends 
and in which it finally ends is the inferior. The one 
is a kind of origin, the other a termination ; and it is 
the superior which is an origin. It might, however, 
seem that in plants the inferior is the more essential c 
part ; for the superior and the inferior are not in the 
same position in them as in the animals. Though in 
relation to the universe they have not the same posi- 
tion, they are similarly situated as regards function. 
For in plants the roots are the superior part d ; for it 
is from them that the nutriment is distributed to the 
parts that grow, and it is from their roots that plants 
receive it, as do animals from their mouths. 

Things which not only live but are also animals have 
both a front and a back. For all animals have sense- 
perception, and it is on account of sense-perception 
that the front and the back are distinguished ; for 
the parts in which the sense-perception is implanted 





"Oaa §€ ra)v C,cpa)v fir) fiovov alcrdrjaecos Koivcovet, 
15 aAAa hvvarai 7roi€icr9ai tyjv Kara tottov fiera- 
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opioitos tols Trporepov €LprjpL€i>OLS tpyto tlvl Kal ov 
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Kal tovto) tt€^)vk6s aKoXovOelv apLOTepov. TOVTO 
8e htrjpOpojTaL jxdXXov iripoLS irepajv. oaa fiev 
yap opyaviKols fxepeui y^poj\x^va (Xiya) 8' otov 

flivrjV jJL€Ta^oXr]V TTOL€LTaL 3 7T€pl fJL€V TCL TOLaVTa 

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Trpo€p)(€TaL s KaOdrrep evLa Ttbv aTroowv, otov ol 

T€ 0(f)€LS Kal TO TO)V KafJLTTWV yil'OS > Kal TipOS TOVTOLS 

a koXovol yrjs evTtpa, VTtdpyzL p<ev Kal iv tovtols 
to Xe^Oev, ov pLr)v Staaeaa^^Tat y opLolcos- 
BO "Otl 8' €K to)v Sz^lqjv r) apx 7 ? rrjs KLvrjGecvs cgti, 

G7][A€LOV Kal TO (j)€p€LV TO, (f)OpTLa TTaVTaS 6776 TOIS" 

dpLCTTepols' ovtojs yap eVSe^erai KLvetaOaL to <f>4pov, 
XeXvfievov tov klvtjgovtos. (olo Kal doKwXLa^ovaL 

paOV €7ll TOLS dpLGTCpOLS' KLV6LV yap 7T€(j)VK€ TO 

706 a Se^LOVj KLveiudaL ok TO dpLGT€pOV.) WGTC Kal TO 

<f)OpTLOV Ol)K €7tI TCp KLVTjGOVTL aAA' €771 TO) KLVTjGO- 

1 5tj Jaeger : o£ libri. 

a Viz. superior and inferior. 
b i.e. from place to place. 



and whence every kind of creature derives it are at 
the front, and the opposite parts to these are at the 

Those animals which not only partake of sense- 
perception but can also of themselves make the 
change from place to place, in addition to the dis- 
tinctions already mentioned, 3 have a further distinc- 
tion of left and right, these being each, like the above, 
distinctions of function and not of position. For the 
part of the body where the origin of change from 
place to place naturally arises is the right in each 
kind of animal, while the part which is opposed to 
this and naturally follows its lead is the left. 

There is a greater differentiation between right 
and left in some animals than in others. All animals 
which make the above-mentioned change b by the use 
of instrumental parts — for example, feet or wings 
or the like — show a greater differentiation between 
right and left in such parts ; those, on the other hand, 
that progress not by means of such parts but by 
moving the body itself in sections — like some of the 
footless animals, such as snakes and the caterpillars, 
and also earthworms — possess, it is true, this differ- 
entiation, but it is not nearly so clearly denned. 

That the origin of movement is from the right side 
is shown by the fact that men always carry burdens 
on the left shoulder ; for then it is possible for that 
which bears the weight to be set in motion, that 
which is to initiate the movement being free. (For 
this reason, too, it is easier to hop on the left- leg ; for 
it is natural to the right leg to initiate movement, 
and to the left to be set in motion.) The burden, 
therefore, must rest not on the part which is to 
initiate movement, but on that which is to be set in 



fieucp Set iiTLKeTodai' idv 8' inl ra> klvovvtl Kal rfj 
dpxfj Trjs KLvqueaJS iTTireOfj, rjrOL 6Xws ov Kcvqaerat 
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rj dpx^j tt]s Kivrjoeojs Kal at it pofioXa'r iravres 
yap rd apiarepd TTpofidXAovrai, Kal ioTwres irpo- 
pe^XrjKaoi 1 rd dpiorepd fi&XXov, av fir} dird tvxVS 
ovpififj. ov yap ra> rrpo^e^Kon Kivovvrai y dXXd 
rep dnofiefiriKOTi- Kal dycvvovTai rots oe^ioTs. 

10 Sta. Tavrrjv Se rr]v alrlav Kal rd Sef id ravrd ion 
TrdvTQJv. 66 ev fiev yap rj apx^j ttjs Kivrjoeos } to 
at/To rraoi Kai iv rq> avTcp ttjv Qeoiv e'xet Kara (f>voiv 
oe^idv 8' iarlv odev r) dpx^j Trjs Kivrjoews ionv. 
Kal hid tovto ra OTpofjLpcoSrj tcov oarpaKoSepfxcov 
$e£td Train iaTtv. ov yap em ttjv eXiKrjv Kivevrat > 

is dAA' irrl to KaTavTLKpv rrdvTa rrpoipx^Tai, olov 


drro tcov Se^Lwv, KaKelvcov iirl ravrd Kivovfievcov 
eavTols, avdyKrj ndvTa $e£td etvat dfiolajs. drro- 
XeXvp.eva 8' e'xovai ra dpicrepd twv £a)wv fid- 
XiaTa dvOpcoTTot Sta to /caret <f>voiv €X eiv ftdXiOTa 

20 TO)V ^CpCOV (f>VG€l 0€ ^XtLOV T€ TO 8e£lOV TOV 

apioTepov Kal Kexo3pio\iivov . Sto Kal to. Septet 
iv toIs dv9pa>7Tot,s fidXcoTa Se£ia ianv. Stcopta/ze- 
vwv Se to>v $e£ia>v evX6yu>s rd dpiuTepd aKivq- 
TOTepd icrn, Kal aTroXeXvyieva /xaAtora iv tovtols, 
Kal at d'AAat 8' dpxal /xaAtara Kara <f>votv St- 
25 copLOfjievai ev tw avOpojircp VTrdpxovai, to t* clvoj 
/cat to eyarpoodev. 

1 irpop€p\r)Ka<ri PSU : irpo^e^Kaai YZ. 

I.e. in the sense that man is right-handed. 



motion ; and if it be placed on that which causes 
and is the origin of movement, it will either not be 
moved at all or with greater difficulty. The manner 
in which we step out also shows that the origin of 
movement is in the right side ; for all men put the 
left foot foremost, and, when standing, preferably 
place the left foot in front, unless they do otherwise 
accidentally. For they are moved, not by the foot 
which they put in front, but by that with which they 
step off ; also they defend themselves with their 
right limbs. Therefore the right is the same in all ; 
for that from which the origin of movement is derived 
is the same in all and has its position by nature in the 
same place, and it is from the right that the origin 
of movement is derived. For this reason, too, the 
stromboid testaceans all have their shells on the 
right ; for they all move not in the direction of the 
spiral but in the opposite direction, the purple-fish, 
for example, and the trumpet-shell. Since, then, 
movement in all animals starts from the right, and 
the right moves in the same direction as the animal 
itself, they must all alike be right-sided. a Now man 
more than any other animal has his left limbs de- 
tached, because of all animals he is most in accord- 
ance with nature, and the right is naturally better 
than the left and separated from it. Therefore the 
right is most right-sided in man. And since the right 
is differentiated, it is only reasonable that the left is 
less easily set in motion and most detached in man. 
Moreover the other principles, 6 the superior and the 
front, are in man most in accord with nature and most 

6 The apxat here are the diaardaeLs of 701 b 19, 705 a 26, 
from the point of view of function rather than position. 



V. OlS fJL€V OVV TO dvO) KCU TO €[Ji7TpOa9eV Sl- 

ravra fiev StVoSa (rwv 8e rerrdpcov rd Svo cnj/zcta 
to is {lev irripvyes to is 8e \elpes Kal ^pa^toves 
30€to*u>). oua 8' iul to auTO to irpoaOev e^et /cat 
to dVco, TcrpaTToSa Kal TroXvTToha Kal dVoSa. 
KaAai yap 7rdSa piepos €tt\ GTjfieup tte^co klvt^tlkco 
Kara tottov Kal yap to 6Vop,a iotKaaiv elXiq^ivai 
aTTO tov ttcoov ol TToSeg. tvia 8' irrl to ai)TO 
e^et to TTpoaBiov Kal to ottlgOlov, olov t<x re 
706 b /zaAd/cta /cat ra arpop^coSr) tcov OGTpaKoSeppLcov 
eiprjrai 8e rrepl avTcdv irpoTtpov iv irtpois. 

Tpiwv 8' ovrcov tottcov, tov dvco Kal pL€CTOV 
Kal KaTWj rd [lev StVoSa to dvco TTpos to tov 
oXov dvco e^etj ra Se 77oAu77oSa 7} dVoSa TTpos 

5 TO pL€GOVy Ta 0€ 0UTO, ^pd? TO KaTCO . atTtOJ^ 8' 

OTt Ta ^tei' dKtvrjra, TTpos ttjv rpocfyrjv Se to d^co, 
7] Se Tpo(f>r] Ik rrjs y^S". Ta Se reTpdrroSa irrl 
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/xi7 dp#d €ivai. rd 8e StVoSa Tipd? to di/oj Std 
10 to dp#d elvaiy /zdAtora S' d dvOpcoiros' /zdAtora 
yap /caTa <f>voiv icrrl Slttovs. evXoycos Se /cat at 
dpyal elcriv diro tovtcov tcov fioptcov rj fiev yap 
dpx^j Tipuov, to S° dvco tov KaTCO Kal to TrpocrOev 
tov omcrOev Kal to $e£iov tov dpLcrrepov TtpacoTepov. 
KaXcos 8' e^et /cat to dvaTraXiv Xeyetv Trept avTcov 3 

a The whole of man is " front," and his " front " is divided 
into superior and inferior ; in a quadruped only that part 
is " front " which is superior in man. 

b P. A. 6Sib It ff. ; H.A. 523 b 21 ff. 

c *Apx7? has here the double meaning of " starting-point" 
and "centre of authority"; see note on De mot. anim. 
698b 1. 



V. Animals in which the superior and the front are 
differentiated, man, for example, and the birds, are 
bipeds (two of the four points being wings in birds, 
and hands and arms in man). But the animals in 
which the superior and the front are in the same 
position a are four-footed (quadrupeds), many-footed 
(polypods), and footless. By " foot " I mean the part 
that is at a point which has connexion with the ground 
and gives movement from place to place ; for the 
feet (?roSes) seem to have derived their name from 
the ground (irkSov). Some animals have their front 
and their back in the same position, for example the 
molluscs and the stromboid testaceans ; with these 
we have already dealt elsewhere. 5 

Now since there are three regions, the superior, 
the middle, and the inferior, bipeds have their 
superior part in a position corresponding to the 
superior region of the universe, polypods and footless 
animals in a position corresponding to the middle 
region, and plants in a position corresponding to the 
inferior region. The reason is that plants lack 
movement, and the superior part is situated with a 
view to nutriment, and their nutriment comes from 
the earth. Quadrupeds, polypods, and footless 
animals have their superior part in a position corre- 
sponding to the middle region because they are not 
erect ; bipeds have it in a position corresponding to 
the superior region because they are erect, especially 
man, the biped most in accordance with nature. And 
it is only reasonable that the origins c should come 
from these parts ; for the origin is honourable, and 
the superior is more honourable than the inferior, and 
the front than the back, and the right than the left. 
It is also true if we reverse the proposition and assert 



15 ws ota to ras* apx^s €V tovtois ewat ravra 
rtfiLwrepa twv dvTiK€L{i€i>wv fioplwv iarlv. 

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Igtiv ipxh> 4 >ave P^ v ^ K TWV ^lpf)^ vwv ' zttzI S' 
avdyKT] ttolvtos avvexovg, ov to fiev Kivetrat 

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tSta KLvrjms VTrdpxet twv dvTiKeLfievwv fiepwv 

25 e/carepaj, irdvTa raura koivtjv dpx'fjv ^X €L Kara2 
ttjv twv elprjjJLevwv fiepwv oviicfyvcnv, Xiyw Se twv 
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/cat twv efiTTpoaOev /cat twv oTTiodev. /caret fiev ovv 
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to Seftov /cat dpiOTepdv Stopt^oucnj, Sta to r^y 

1 c>7?\of 6Vi (Leon, manifestum est quod, etc.): brfKovbn libri. 
2 Kara P Leon. : om. ceteri. 

° the three pairs of " dimensions " (70 i b 19). 



that, because the origins are situated in these parts, 
they are therefore more honourable than the opposite 

VI. It is clear, then, from what has been said that 
the origin of movement is on the right. Now in 
anything continuous of which part is in motion and 
part at rest (the whole being able to move while one 
part stands still), there must be, at the point where 
both parts move in opposite movements, something 
common to both which makes these parts continuous 
with one another (and at this point must be situated 
the origin of the movement of each of these parts, 
and likewise also of their immobility) : it is evident, 
therefore, that in respect of whichever of the above- 
mentioned contraries a the individual movement of 
each of the opposite parts takes place, there is in 
all these cases a common origin of movement by 
reason of the interconnexion of the said parts, namely, 
of the right and the left, the superior and the inferior, 
the front and the back. The differentiation accord- 
ing to front and back is not one which applies to 
that which moves itself, because nothing possesses a 
natural movement backwards nor has the moving 
animal any distinction in accordance with which it 
can make a change from place to place in each of 
these two directions b ; but there is a differentiation 
of right and left, superior and inferior. All animals, 
therefore, which progress by the employment of in- 
strumental parts have these parts differentiated, not 
by the distinction between front and back, but by the 
other two pairs, first, by the distinction of right and 
left (for this must immediately exist where there are 

B In other words an animal cannot divide itself into two 
parts, one of which goes forwards and the other backwards. 



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1 5' PUZ: om. SY. 2 £ X « Z: om. cet. 

° 'i.e. the distinction of superior and inferior. 

b Namely, the soul situated in the heart (Mich.). 

c The legs move in pairs, either the front and back legs 
on the same side together, or the front leg on one side with 
the back leg on the other (c/. 704? b 7). 


two things), and, secondly, by the distinction which 
must arise as soon as there are four things. a 

Since, then, the superior and the inferior, and the 
right and the left are connected with one another by 
the same common origin (and by this I mean that 
which controls their movement b ), and since in any- 
thing which is to carry out the movement of each 
part properly the cause of all the said movements 
must be somehow defined and arranged at the right 
distance in relation to the said origins, namely, 
those in the limbs, which are in pairs opposite or 
diagonal to one another,* (and the cause of their 
movement is the common origin from which the 
movement of left and right and likewise of superior 
and inferior in the animal's limbs is derived), and 
since this origin must in each animal be at a point 
where it is in more or less the same relation to each 
of the origins in the said parts/ (VII.) it is, therefore, 
clear that movement from place to place belongs 
either solely or chiefly to those animals which make 
their change of place by means of two or four points. 
And so, since this condition occurs almost exclusively 
in red-blooded animals, it is clear that no red-blooded 
animal can move by means of more than four points, 
and if an animal is so constituted by nature as to 
move by means of four points only, it must neces- 
sarily be red-blooded. 

What actually occurs in animals is also in agree- 
ment with the above statement. For no red-blooded 
animal can live for any time worth mentioning if it be 

d There are two kinds of dpxai in, e.g., a quadruped, (a) 
those in each of the four legs and (6) the central apxv in the 
heart ; the former must each be approximately equidistant 
from the latter. 



cos" ei7reiv, rrjs re Kara rorrov Kivrjaews, Kau r)V 
eKiveiro avvex^S ov Kal fir) hLrjprjjjievov, ov hvvarai 
Koivcovelv rcbv 8' dvalficov re Kal rroXvrrohcov evia 
hiaipovpceva hvvarai tjjv ttoXvv %p6vov eKaarco 
rcbv fiepcbv, Kal KiveiaOai rr)v avrrjv rjvirep Kal 
30 nplv hiaipeOrjvai KLvrjcnv, olov ai re KaXovpcevai 
GKoXoirevhpai Kal dXXa rcbv evroficov Kal 7TpofirjKcbv 
rrdvrcov yap rovrcov Kal to oiriadev fiepos errl 
707bravr6 iroieirai rrjv rropeLav rcb epLTTpoaQev. alriov 
he. rod hiaipovfxeva tfqv on, KaOairep dv el re 
crvvex^S eK ttoXXcov eirj i^wcov ovyKei\xevov > ovrcos 
eKaarov avrcbv ovvear-qKev. <f>avep6v he rovro Ik 
rcbv irporepov elprjjjievcov, hiori rovrov e\ei rbv 
6 rporrov. 

Aval yap r) rerrapui crrffxeiois TrecbvKe KiveiaOai 
ra pLaXiura avvearrjKora Kara, tfivatv, ofxolcos he 
Kal oaa rcbv eval\xcov dirohd eariv. Kal ydp ravra 
Kiveirai rerrapoi crrjfieiois, Si* obv rrjv kivtjctiv 
rroLelrai. hvcrl ydp xP c ^l 1€va ^poepxerai Kafx- 

10 Trots" to yap he£iov Kal dpiorepov Kal to irpoadiov 
Kal orrloBiov ev rcb rrXdrei eurlv iv eKarepa. rfj 
KafiTrfj avrotSt l*€v t£> npos rrjv Kecf)aXr)v 
fiepet to rrpooOiov arjfjLeiov he^iov re Kal api- 
orepoVy ev he rcb irpos rrjv ovpdv ra orriadia 
crrjfjieia. hoKel he hvoiv cnqpLeLoiv KiveiaOai, rfj r* 
e/JLTTpocrOev d(f>fj Kal rfj varepov. alriov S' on 

15 urevov Kara irXdros eariv, eirel Kal ev rovrois to 
he^iov rjyeirai, Kal avrairohLhcooi Kara to oiriodev, 
toairep ev roig rerpdrroaiv. rcbv he Kapufieaiv 
alriov to fJirjKos' coenrep ydp ol [xaKpol rcbv dv- 
dpcoiTcov Xophol fiahi^ovai, Kal rod he£iov dfxov 
° Centipedes. 



divided into several parts, and can no longer partake 
of the motion from place to place whereby it moved 
while it was still continuous and undivided. On the 
other hand, some of the bloodless animals and poly- 
pods can, when they are divided, live in each of 
these parts for a considerable time and move with 
the same motion as before they were divided, the so- 
called scolopendrae, a for example, and other elongated 
insects ; for the hinder part of all these continues to 
progress in the same direction as the fore-part. The 
reason why they live when they are divided is that 
each of them consists as it were of a continuous body 
made up of many animals. And the reason why they 
are of this kind is clear from what has been said above. 

Animals which are constituted most in accordance 
with nature naturally move by means of two or four 
points, and likewise also those among the red-blooded 
animals which are footless ; for they too move at four 
points and so effect locomotion. For they progress 
by means of two bends ; for in each of their bends 
there is a right and a left, a front and a back in 
their breadth — a front point on the right and another 
on the left in the part towards the head, and the two 
hinder points in the part towards the tail. They 
appear to move at two points only, namely, the points 
of contact with the ground in front and behind. The 
reason for this is that they are narrow in breadth ; 
for in these animals too, as in the quadrupeds, the 
right leads the way and sets up a corresponding move- 
ment behind. The reason of their bendings is their 
length ; for just as tall men walk with their backs 
hollowed b and, while their right shoulder leads the 

b \opd6s is the opposite of Kv<p6s, hunchbacked (Hippocr. 
Fract. 763). 



7 ° 7b etS' to Trpoodev -qyovfievov to dpiGTepov Icr^lov els 

o rovTTiaOev fiaXXov dnoKXivei, Kal to jxeGov kolXov 
ylverai Kal AopSoV, ovtoj Set voelv Kal tovs otbeis 
Kivovpiivovs irrl rfj yfj XopSovs. Grjfxetov 8' ore 
dfiotcos Kivovvrai rols TerpdnoGLV • iv fiepei yap 
fjL€TafidX\ov(Ji to kolXov Kal to Kvprov. orav 
yap TrdXiv to dpiGTepov tcov TrpooBlcov rjyrjcnrjTaL, 

25 il; evavrias rrdXiv to koiXov ylveTai' to yap Se£idv 
ivTos ndXiv ylveTai. o-qfjieTov Se£i6v irpooBiov 
i<f> y ov A, dpiGTepov e\/>' ov B, dirloBiov Se£idv ifi 
ov r, dpiGTepov icfS ov A. 

Ovtoj Se KivovvTai tcov fiev x € P <ja ^ OJV °l o<f>eis, 
tcov 8' ivvopcov at iyxiXeis Kal ol yoyypoi Kal at 

30 fivpaivai, Kal tcov ciXXojv doa e^ei tt)v fiopcbrjv 
d<f>LOJoetTT€pav. ttXtjv evia fxev tcov ivvSpcov tcov 
toiovtcov ovSev exec TTTepvyiov, olov ai fivpaivai, 
708 a dXXd xprjTac tt) QaXaTTTj coGnep ol ocf>eis rfj yfj 
Kal rfj BaXaTTT] (veovot yap ol ocheis dfiolcos 
Kal orav KLvcovTat irrl Trjs yrjs)' Ta Se Sv e'xei 
TTTepvyca (jlovov, olov ol T€ yoyypoi Kal al iy- 
xiXeis Kal yevos ti KeoTpecov, ot ylvovrai iv 
5 Tjj XlfivT] tt) iv Stoats'. Kal Scd tovto Tats* 
Karats iXaTTOOi KivovvTai Iv tco vypco 77 iv ttj 
yfj Ta tftjv eicoOoTa iv rfj yfj, KaOdrrep to tcov 
iyxiXecov yevos. ol Se Svo TTTepvyca k'xovTes tcov 
Keorpecov rfj KapLirfj dviod^ovGiv iv tco vypco Ta 
reTrapa orjfxeta. VIII. Tots' 8' o<f>eotv atriov Trjs 

10 dnoSlas to Te ttjv tbvoiv pbrjdev noieiv \xaTi\v ) 

On the Boeotian coast of the Corinthian Gulf, the Tipha 
of Pans. ix. 32. 3. 

b i.e. two of its ** points " are fins and the other two are 
made by bends. 


way forward, their left hip inclines towards the rear 
and the middle of the body becomes concave and 
hollow, so we must suppose that snakes too move 
upon the ground with their backs hollowed. And 
that they move in the same manner as quadrupeds 
is shown by the fact that they change the concave 
into the convex and the convex into the concave. 
For when the left forward point is again leading 
the way, the concavity comes in turn on the other 
side, for the right again becomes the inner. Let 
the front point on the right be A, and that on the 

left B, and the rear point on the right C, and that on 
the left D. 

This is the way that snakes move as land-animals, 
and eels, conger-eels and lampreys and all the 
other snake-like creatures as water-animals. Some 
water-animals, however, of this class, lampreys for 
example, have no fin and use the sea as snakes 
use both the sea and the land ; for snakes swim in 
just the same manner as when they move on land. 
Others have two fins only, conger-eels for example, 
and ordinary eels and a species of mullet which occurs 
in the lake at Siphae. a For this reason too those 
which are accustomed to live on land, the eels for 
example, move with fewer bends in the water than 
on dry land. The kind of mullet which has only two 
fins makes up the number of four points in the water 
by its bends. b VIII. The reason why snakes are 
footless is, first, that nature creates nothing without 



dXXa iravra irpos to dpcoTov drrofiXeTTOvoav eKaoTCp 
tcov ivSexofievajv, hiaaw^ovoav iKaarov rrjv lolav 
ovolav Kal to rt r)v avTCp elvat' ert 8k Kal to irpo- 
Tepov r)p2v elprjfiivov, to tcov evalfitov firjOkv oiov 

T* €ivai nXeLOOl KLV€Lo6ai tTr)fjL€LOLS Tf T€TTapOlV. 

€K tovtcov yap (fyavepov otl tcov ivai^cov oca kclto. 

15 to ptrjKos do-vfJifieTpd Igti irpos rrjv dXXrjv tov 
oojpLaTos <j>voiv t KaOd-nzp ol ocfyeis, ovOkv avTCov 
otov 6* vitottovv elvai. rrXelovs fikv yap T€TTaptov 
oi>x otov T€ aura rrooas 4yjeiv (dvaifia yap av rjv), 
exovTa ok ovo 7rooas rj T€TTapas o-^eSoV rjv av 
aKivrfTa TtdpLirav ovtco fipaoetav dvayKatov elvai 

20 Kal dvcocjteXfj Trjv klv7]olv. 

"Anay 8k to vttottovv i£ dvdyKrjs dpTiovs e^€t 
tovs 7r6has' oaa fikv yap dXoei xP c ^} JL€va l^ovov 

7TOl€LTai T7JV KaTQ TOTTOV fl€TafioXr)v , Ol)9kv TTo8tOV 

TTpos ye TTjv ToiavTTjv oetrai Kivrjaw ooa 8k 
XprfTai jxkv dXazi, pirj ecrrt 8' avTols avTapKrjs 

25 avTTj r) Kivrjois dXXd Kal iropelas tt poooiovT ai, 8rj- 
Xov cos tols fjikv /34Xtlov tols S' ^aAAo)?} oXws 
dovvaTOV 1 TTOpeveodai. [Sioti tt&v ^coov dvayKatov 
dpTiovs zyjEiv tovs TrdSas".] 2 ovorjs yap Trjs 
TOiavTTjS [AeTafioXrjs KaTa fiepos, aAA' ovk ddpocp 
iravTi tco crai/xaTi KaOdnep Trjs dXoetos, dvayKatov 

30 ioTt, toIs jxkv fievetv jjteTafiaXXovTcov twv noocbv 


inl ra (xevovTa to fidpos. htoirep ovt€ Tptol fikv 

1 <#XXws> 6Xws abyvarov] oXws abvvarov <&XXws> Farquharson. 
1 6l6tl . . . Trodas om. PSU : tan qua m glossema del. Jaeger. 

a JMich.'s explanation of this passage is that certain poly- 
pods, which can walk with an uneven number of legs (c/. 



a purpose but always with a view to what is best for 
each thing within the bounds of possibility, preserv- 
ing the particular essence and purpose of each ; and, 
secondly, as we have already said, because no red- 
blooded animal can move by means of more than four 
points. It is clear from this that all red-blooded 
animals whose length is out of proportion to the rest 
of their bodily constitution, like the snakes, can none 
of them have feet ; for they cannot have more than 
four feet (for if they had, they would be bloodless), 
whereas, if they had two or four feet, they would be 
practically incapable of any movement at all, so slow 
and useless would their movement necessarily be. 

Every animal which has feet must necessarily have 
an even number of feet ; for those which move from 
place to place by jumping only do not require feet 
(at least not for this movement), while those which 
jump but do not find this mode of locomotion suffi- 
cient by itself and need to walk also, must clearly 
either progress better with an even number of legs 
or else cannot otherwise progress at all. a For since 
this kind of change from place to place is carried out 
by a part and not, like jumping, with the whole of 
the body at once, some of the feet during the change 
of position must remain at rest while others are in 
motion, and the animal must rest and move with 
opposite legs, transferring the weight from the legs 
in motion to those at rest. Hence no animal can 

708b 5 ff.), would walk better with an even number; quad- 
rupeds and bipeds, on the other hand, cannot walk at all with 
an uneven number of legs. Farquharson's insertion of SlWws 
seems therefore a certain emendation : the omission of d\\ws, 
however, in our mss. would be better accounted for if it is 
inserted before SXws rather than before iroptveadat. 




708 b ovdkv ovQ* eVt 1 y^pd}\xevov fiaSl^eiv otov re* to [lev 
yap ovdkv SXtos v7T0OTr)\xa e^et icf> y to to rod 
awjiaros e£et jidpos, to Se Kara tt)v erepav 
avrWeuiv pbovrjv, coot dvayKatov avro ovtcos 

€7TL)(€LpOVV KlVElodai 7TL7TTCIV '. OOCL Se 7ToXv7ToSd 

5 ioriVy otov at OKoXoTrevhpai, tovtols Svvarov fiev 

/Cat OLTTO 7T€plTTU)V 7ToSdjV TTOpzlcLV ytVeoffat, Ka9(17T€p 

nrfpcoarj tcov irohujv, Sid to ttjv tcov dvTioToi)(cov 
ttoSwv KoXofltoaiv laodcu rep A ot77 a) 7rXrjdeL tcov 
itf> y e/carepa 7roSa;v* ylveTai yap tovtols otov 

10 €(f>eX£l$ TOV 7T€7T7)pCO[jL€VOV flOplOV TOIS dXAoi$ 3 

dAA* ou fidSicris. ov pbrjv dXXd <j>avep6v ort fieXTiov 
dv /cat Taura ttololto ttjv fjLeTafioXrjv dpTiovs 
€)(ovTa tovs noSaSy /cat {jltjOcvos iXXeiTroVTos > aAA 
dvTtGTOLXovs k'xovTa tovs 77o8as" ovtco yap (dvy 2 
avTWV dviad^eiv t€ SvvatTo 3 to fidpos /cat fir) 
15 TaAai'Teueti^ eVt OaTepa {jl&XXov, et a^rtWot^a 
epelorfiaT* e^ot /cat jjirj Kevrjv ttjv eTepav ychpav 

TWV 4, dvTLK€LfJL€VWV. 770o/?atWt 8' atf)* €KaT€pOV 

tcov fjLeptov ivaXXd£ to T/opevofievov ovtco yap 
els TavTo Tco i£ ^PXV^ oxh\ x,arl yw€T& L V *<ard- 

20 "Ort pcev ovv dpTiovs e'x et rot's" 77d8as' rrdvTa, 
/cat Sta tIv aiTiaVt etp^rar IX. 6Vt 8' el firjOev 
rjv Tjpefjiovv, ovk av rjv Kapa/jts oOS' evOvvuis y e/c 
TCovSe SrjXov. ecrrt yap /ca/xi/fts* fiev r) i£ evdeos rj 
els 7T€pL(f)€p€g rj els ycoviav pi€Taf$oXr] ) evOvvats 
8' rj €K QaTepov tovtcov els evdv. iv aTrdoats Se 

25 Tat? elprjfjLevaLS jxeTa^oXats dvdyKrj Trpos ev orjjjieiov 

1 o#re Tpiai fxh ovdkv ovd" evi Jaeger : ov5e (ov8£ om. PYZ) 
rptal fxkv ovdh ovdevi libri. 2 B.v add. Jaeger. 



walk using either three legs or one leg ; for if it uses 
one leg it has absolutely no support on which it is to 
rest the weight of the body, and if it uses three it will 
rest it on a pair of opposite legs, so that, if it attempts 
to move thus, it necessarily falls. Polypods, however, 
for instance the scolopendrae, can achieve progression 
with an odd number of legs, as they can be immediately 
seen to do if you mutilate one of their feet, because 
the maiming of some of the feet in the opposing rows 
is compensated by the greater number of feet still 
remaining on either side ; the result is that the 
maimed leg is as it were dragged along by the others, 
and the animal does not walk properly. However, 
it is clear that these maimed animals would achieve 
the change of position better if they had an even 
number of feet, that is, if none were lacking and they 
had all the feet in the corresponding rows ; for then 
they would be able to distribute their weight evenly 
and would not sway to one side, if they had corre- 
sponding supports on each side and had not one space 
in the opposite rows devoid of a leg. An animal, 
then, when it walks progresses by means of each of 
its limbs alternately ; for thus its state is restored so 
as to be identical with its original form. 

It has now been established that all animals have 
an even number of feet, and the reason for this has 
been stated. IX. That, if nothing were at rest, there 
could be no bending or straightening is clear from the 
following considerations. Bending is the change from 
what is straight to what is curved or angular; straighten- 
ing is the change of either of these to what is straight. 
In all the above changes the bending or straightening 

3 8vvatro SCripsi : dvuarai Z : duvaivro ceteri. 
4 tt]v ante t&v add. Z. 



TYjV KOLfJLlpW Tj TTJV €v6w<7lV yiV€odai. aAAa fJLTJV 

Kdfiifjecvg ye jjltj ovarjs out' dv nopeta ovt€ vevais 
ovre TTrrjcris rjv. ra fiev yap vttottoSol eVeiS^ iv 
eKarepa) tluv avriKeijiivcav gkzAwv iv jxipei toTarat 
Kal to fidpos t<J)(€L s avayKcuov darepov irpo- 
30 fiaivovTos Baripov TroieiaOai Kapuffiv. laa re yap 

7T€<f)VK€V €y€ lV T( ? ^V K€L T( * dvTLCTTOl)(a KCoAdj Kal 

opdov Set elvat to V(f>€OTOS to> j3dp€L f olov KaOeTov 
TTpog TTjv yrjv. oTav Se TTpojSaivr], ytVerat rj 
709 a viTOT^lvovaa Kal Svvajj.ei'7] to \iivov fiiyeOos Kal 
TTjv fxeTa^v. eVet S' tua ra KcbXa, dvdyKT) Kapufjat 
to fxivoVy rj eV tw yovaTi rj eV ttj Kajjujjei, olov 
et ti dyovaTOV et'77 tcov fiaSi^ovTtov. arjfJLeTov S' 
5 oti ovtojs e^et* et ydp tls iv yfj 1 jSaStfot napa 
TolxoVy rj ypa(f>opL€V7] eoTat ovk evOeia dXXa cr/<oAta, 
Sta to iAaTTW fiiv KapLTTTOVTOS ytveaOai ttjv 
ypacfyoiiivrjVy /xet£a> §' tWa/xeVou Kal i^alpovTOS. 
'Ei'Se^erca /xeVrot Kivelado.1 Kal fxr] e^oVTog Kafx- 

7TTJV TOV VKiXoVS, 0)G7T€p TO. 7TatSta ipiTOVGlV. Kal 

io 7T€pl twv iAecfrdvTojv 6 TraXaiog r\v Xoyos toiovtos, 
ovk dXrjOrjs div. KiveiTat Se Kal tol TOiavTa 
Kajjapeajg yLVop.ivrjs iv rats' wfiOTrXaTais r) rots* 
igx^ols. aXX opQov ovoev SuYatr' dv Tropevdrjvai 
Gvvex&s Kal da^aAcos", KivrfieLt] V dv olov iv 
Tals TTaXaloTpais ot Sta Trjs k6v€qjs jrpoiovTzs eVt 
twv yovaTtov. ttoXv yap to dva> fxipog, ajcrre 
1 iv yfj libri : locus corrnptus et lacuna mutilatus. 

° It does not actually do so because it is not long enough 
to reach the ground : and so, as is explained below, the other 
leg must be bent to enable it to do so. 

b Avvafj.i$ in mathematics is used of a "power," generally 
the second power, i.e. the square of a number : similarly in 
geometry dwajxis and dvva/jLcu. are used of the figure which 


must necessarily be relative to a single point. Further, 
if there were no bending, there would be no walking 
or swimming or flying. For since animals with feet 
stand and rest their weight alternately on each of 
their two opposite legs, as one leg advances the other 
must necessarily be bent. For the corresponding 
legs on either side are naturally equal in length, and 
the leg which supports the weight must be straight, 
at right angles, as it were, to the ground. But when 
a leg advances, it is assuming the position of the side 
subtending a right angle, the square upon which 
equals the squares b on the side which is at rest and 
the line between the two legs ; but since the legs 
are equal, the leg which is at rest must bend either 
at the knee or, in any kneeless animal that walks, at 
the joint. That this is so is shown by the fact that 
if a man were to walk on the ground alongside a wall 
[with a reed dipped in ink attached to his head], c 
the line traced [by the reed] would not be straight 
but zigzag, because it goes lower when he bends and 
higher when he stands upright and raises himself. 

It is possible, however, to move even if the leg has 
no bend in it, as happens when children crawl. (The 
old account attributed such motion to elephants, but 
it is untrue.) Movement of this kind takes place 
through a bending in the shoulders or hips. But no 
creature could walk erect in this way continuously 
and safely, but could only move like those who drag 
themselves forward through the dust in the wrestling- 
school on their knees. For the upper portion of the 

can be formed by constructing squares on the side of, e.g. a 

c The text here is corrupt and something has fallen out in 
all our mss. : the words here bracketed are supplied from the 
explanation given by Mich. 



15 Set fiaKpov elvai to kqjXov el Se tovto, Kapufjw 
dvayKalov elvai. e.7rel yap earrjKe irpos dpBrjv, 
16 b el aKapLTTTOv eoTai to Kivovfievov els to irpovdev* 
fj Kara7TeoelTaL eXdrrovos Trjs opOrjs ycvojJLevrjs, r) 
ov irpofirjueTai. el yap opOov ovtos Barepov aKeXovs 
ddrepov earai tt pofiefifjKos , fxel^ov earai, taov ov 
hvvrjoerai yap tovto to t rjpefiovp Kal ttjv vtto- 

20 Teivovoav. avdyKf] dpa KapLTTTeaOac to Trpo'Cov, Kal 
Kapafjav dpua eKTeiveiv QaTepov, eKKXlveiv Te Kal Sta- 
fie/3r]KevaL Kal enl Trjs KaBeTOV pLeveiv laoaKeXes 
ydp ylveTai Tplyojvov ra KcbXa, Kal r) Kecf>aXr) ylve- 
tcu KaTWTepov } orav KaBeTos fj eft rjs fiefirjKev. 

25 Ta S' a7ToSa tol puev KvpualvovTa upoep\eTai 
(tovto Se Slttws avyL^alvei- t<x [lev yap eirl 
Trjs y?js, KaOairep oi ocf>eis } tcls Kaunas iroiei- 
Tai, to. S' els to avw y tbonep al KapLrrai), r) Se 
KvyLawis KafiTTrj eoTtv tgl 8' IXvcmdaei y^p&iieva, 

so KaOairep Ta KaXov )xeva yrjs evTepa Kal fiheXXai. 
TavTa yap to> fxev rjyovpieva) irpoepyeTai, to Se 
Xoiitov awfia nav rrpos tovto avvdyovac, Kal tov- 


<f>avep6v 8' QTi el pir) al Svo Trjs fitas pbel^ovs rjcrav, 

1 et 8.Ka.}iirTOv tarai rb Kivov/Aevov eis rb irpbaQtv om. PSU 
Bekker: el et irpbadev om. Z. 

° Let AB be the stationary leg and 
V AC the advanced leg, which are by 

hypothesis of equal length. If the right- 
\^ angled triangle ABD is constructed its 

hypotenuse AD must be longer than 




body is large, and therefore the leg must be long ; and 
if this is so, there must necessarily be a bending. For 
since a standing position is perpendicular, th e leg which 
is moved forward, if it is to be unbent, will either fall 
as the right angle becomes less, or else it will not ad- 
vance at all ; for if, while one leg is at right angles, the 
other is advanced, the advanced leg will be greater and 
at the same time equal ; for it will be equal to the leg 
which is at rest and also to the side subtending the 
right angle. a The advancing leg must therefore be 
bent, and the animal, as it bends it, must at the same 
time stretch the other leg and lean forward and make 
a stride and remain in the perpendicular ; for the legs 
form an isosceles triangle and the head becomes 
lower when it is perpendicular to the base of the 
triangle. 6 

Of animals which are footless, some advance with 
an undulating motion — this can be of two kinds, for 
some animals, for example snakes, make their bends 
on the ground, while others, for instance caterpillars, 
make them upwards — and undulation is bending. 
Others move by crawling, like the earthworms and 
leeches ; for these advance with one part leading the 
way, and then draw up all the rest of their body to it, 
and in this manner make the change from place to 
place. It is plain that, if the two lines which they 

b When the stride has been completed the result is an 
isosceles triangle formed by the two legs and the ground ; the 
head, which is necessarily lower than when the legs were 
together, is perpendicularly above the base. 



709 b ovk av ehvvavTo KiveZoOaL tol KVjxalvovra tcov 
l^cocov. eKTaOelorjs yap Trjs KajJLTrrjSy el tcrrjv 
Karetx^i ovOev av Ttpor\eoav i*vv 8' vrrepfidXXei 
€Krad€Lcra 3 Kal rjpefjirjoavTOS tovtov eirayei to 

'Ey Traoais he tols XexOelcrais fJLerafioXaTs to klvov- 
5 jxevov ore fxev eKTeLvofievov els ev9v 7rpoepxeTaL t 
ore he (jvyKa\XTTTo\ievov 3 tols fxev rjyovfjLevois 
fiepeoLV ev6v yivojievov 3 tols 8' enopLevois uvy 
KafjLiTTOV . TTOieiTai he Kal tol aXXofxeva navTa 
Kafiifjiv ev tw vrroKeijievcp \xipei tov crtbfxaTos, 
Kal tovtov tov Tpouov e\ovTa aAAerai. Kal tol 
7TeTOfJL€va Be Kal tol veovTa 3 tol jxev tols TTTepvyas 
10 evQvvovTa Kal KOLfATTTOVTa TreTaTai, tol he tols 
TTTepvylois, Kal tovtcov tol jiev rerrapcrt ra he 
hvolv 3 oua TrpofJLrjKevTepa ttjv fiopcj)rjv 3 cooirep to 
tcov eyxeXecov yevos' rrjv he Xolttov klvt)ulv olvtI 


fxeva vely Kadairep €tp^rat irpoTepov. oi he TrXaTets 
15 tcov IxOvcov Ttj jxev tw rrXaTei xpcovTaL T °v ocbfiaTOs 
avTi TTTepvyltoVy Trj he TTTepvyiois hvcrtv. tol he 
TTOL/JLTTav irXaTea 3 Kadairep 6 f$6.TOS 3 avTots tols 
TTTepvylois Kal Tals eo^arats' tov ocofxaTos trepi- 
tfiepelais evBvvovTa Kal KapLTTTOVTa iroielTai ttjv 

20 X. y A7Toprjoreie 8* av tls tocos ttcos KivovvTai 
TeTTapoi crqixeiois oi opvides, rj TreTOfievoL rj rropevo- 
fxevotj cos elprjfievov otl navTa tol evaifxa KiveiTai 
TeTTapoiv. ovk eiprjTaL he 3 aAA' otl ov TrXeloGLV. 
ov fir)v aAA' ovt av TreTeodaL hvvatvTO a<f>atpe- 

a The bend is represented as two lines forming an angle; 


form were not greater than the one, a movement would 
be impossible for animals which advance by undula- 
tions. For, when the bend is extended, they would 
not have made any advance, if it subtended an equal 
line ; whereas, in fact, it is longer when it is extended, 
and then, when this part has come to a standstill, 
the animal draws up the rest. 

In all the above-mentioned changes that which 
moves advances by first extending itself straight out 
and then curving itself — straightening itself out with 
its leading parts and curving itself in the parts which 
follow. All animals, too, which jump make a bend 
in the lower part of their body and jump in this 
manner. Animals also which fly and those which 
swim, fly by straightening and bending their wings 
and swim with their fins, some fish having four 
fins and others, namely those which are of a more 
elongated form (eels for example), having two fins. 
The latter accomplish the rest of their movement 
by bending themselves in the rest of their body, as a 
substitute for the second pair of fins, as has already 
been said. Flat-fish use their two fins, and the flat 
part of their body instead of the second pair. Fish 
that are entirely flat, like the ray, manage to swim by 
using their actual fins and the outer periphery of their 
body, which they alternately straighten and bend. 

X. A question might perhaps be asked as to how 
birds, whether flying or walking, can move at four 
points, in view of the statement that " all red-blooded 
animals move at four points." But this is not exactly 
what we stated ; what we said was " at not more than 
four points." However, they could not fly if their 

these two lines together must be longer than the line which 
subtends their angle. 

R '2 515 



25 a<f)aipeQei<ja)v s eirel ot3S' dvOpamos fiaSi^ei pur] 


etprjrai, Kapafjei Kal e/craaet 7roiarai ttjv /xera- 
fioXrjv dwavra yap els to vTTOKelpievov p-ixP 1 Tlv ®$ 
olovel crvvvireLKov 1 irpoepxeTaL, war* dvayKoiov s 
el pirj /cat kolt dXXo piopiov yiverai rj Kapuftis, aXA' 
so oQev ye rj dpx^] toi? piev oXorrrepois tov irrepov, 
tols 8' opviGi rrjs TTTepvyos s rots 8' d'AAots* tov 
dvdXoyov puoplov, Kaddrrep tols IxOvctlv. tols 8\ 
cou7rep ol 6<f>eis s ev rats KapLTTals rod acvpcaTos 
710 a eoriv rj dpx^l Trjs Kapupetos* to 8' ovpoirvyLov ian 


KaOdirep tcl TTiqhdXLa tols 7tXolol$. dvayKatov Se 

KCLL TCLVTa €V TTj TTpOdSvOei KapL7TT€LV . 8t07T£p TCt 

d<f)Vcos exeL irpos ttjv elpr^pLevrjv XP^ GIV > OLOV T€ 
Taws Kal tols dXeKTpvoGL Kal oXcos tols p^rj tttt^tl- 


drrXcos ovOev k'xei ovpoirvyLov, coaTe KaBduep d- 
TTTjoaXov ttXolov c^epeTaL, Kal ottov av TVXTl ^KaoTOV 


olov KavdapoL Kal parjXoXovOaL, Kal tcc dveXvTpa, 
olov pteXiTTai Kal otjyrjKes. Kal tols p<r} ttttitlkols 
dxpelov to ovpoirvyLov Igtlv, olov TOLS Te lTOp<f>V- 
pLcocTL Kal epcobLols Kal iraoL tols ttXcotols' dXX 
dvTi tov ovpoirvyLov TTETavTaL tovs irohas diro- 

1 oiovd crvvvirelKOv Z : olov eis VTreiKOf ceteri. 

Lit. tl creatures with undivided wings." (The Greek 
here has different words for the wings of insects and those 
of birds.) 

b Lit. creatures with cloven wings (i.e. made up of feathers) 
as opposed to insects which have undivided wings. 


legs were taken from them, or walk if their wings 
were taken from them, just as a man cannot walk 
without moving his shoulders to some extent. All 
things, as has been said, make their change of position 
by bending and stretching ; for they all progress 
upon that which, being beneath them, also as it were 
gives way to them up to a certain point ; so that, 
even if the bending does not take place in any other 
part, it must at any rate do so at the point where the 
wing begins in flying insects a and in birds, and where 
the analogous part begins in other animals, such as 
fishes. In other animals, snakes for example, the 
beginning of their bending is in the joints of the body. 

In winged creatures the tail is used, like the rudder 
in a ship, to direct the flight ; and this too must bend 
at the point where it joins the body. Flying insects 
also, therefore, and those birds 6 whose tails are ill- 
adapted for the purpose just mentioned, peacocks, 
for example, and domestic fowls and, generally, those 
birds which are not adapted for flight, cannot keep 
a straight course. Of the flying insects not a single 
one possesses a tail, so that they are carried along 
like rudderless ships and collide with anything that 
they happen to meet. The same is true of sheath- 
winged insects , c such as beetles and cockchafers, 
and the sheathless insects, such as bees and wasps. 
The tail is useless in such birds as are not adapted 
to flight, the porphyrio/* for example, and the heron 
and water-fowls in general ; these fly stretching out 

c Coleoptera. 

d The identity of this bird is disputed. W. W. Merry (on 
Aristoph. Aves, 707) suggests some kind of coot ; D'A. W. 
Thompson (on II. A. 509 a 11, 595 a 13) suggests the purple 
coot or the flamingo. 



reivovra, /cat xP CjJVTai aVT ovpoirvyiov rots 

15 (TKeXeCTL TTpOS TO KCLT€v6vV€lV TTjV 7TTT}UIV . jS/Xl- 

Seta 8' r) TTrijais tqjv 6Xo7TT€pcov iarl /cat dadevrjg 
Sid to /X19 /card Xoyov 4\'€ty rrjv tojv TTTepwv <f)vatv 
7Tpds to tov Gcojiaros fidpos, dXXd to fiev ttoXv, 
ra he fiLKpd /cat daOevrj. tooTTtp av ovv el oA- 

20 TrXoVVy OVTCO TCLVTa Tjj 7TTT}G€l XPV rat " /Cat Tj 

daOeveta he avTtov re tcov TTTepcov /cat 77 Trjs 

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8' OpVldoJV TO) }.l€V TCLCi) TO OVpOTTVyLOV OT€ fieV 

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fidXAeiv ovOev dxfceXei. VTrevavTicos 8' k'xovcriv ©t 

25 opvides TOIS oXoTTTepOLS TTjV TO)V TTTepOJV <f)VCFW , 

uaAiora 8' ot ra^tora auTtDi; TreTOfievoi. tolovtol 
8' ot ya/jLipcovvxes' tovtols yap rj TaxvTrjs ttJs 1 
7TTiijo'€GJs xprjcrifjios rrpos tov fHov . d/cdAoi;0a 8' 
adTtDy eoiKev elvai /cat Ta Aot7ra jiopia tov aw- 


30 airavTotv ut/cpd /cat avxV v °v ^a^us", GTrjOos 8' 
laxvpov /cat dfi;, dfi> /xev 77pd? to evTovov etvat, 
Kaddrrep dv el ttXolov rrpojpa Xe^tohovs, laxvpov 
he Tjj 7T€pi(j)vcr€t Trjs oapKos, tV dircoQeiv Svvrjrai 
7i0bTdy 7Tpocr7TL7TTOVTa depa } /cat tovto paoicos /cat (jltj 
fi€Ta 7t6vov. Ta 8' OTXioQev Kov<f>a /cat crvvrjKOVTa 
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pur) avpovTOL tov depa 8td to TrXaTos. 

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tovtoVj to he fieXXov ^wov 6p66v /?a8t€icr0at StoTt 
8t770fv T€ dvayKolov ioTtv elvai, /cat ra fiev dvco 

TOV CFCQfjLCLTOS ^P^] KOV(f>OT€pa €X €lV T ^ ^' V<f>€GTO)Ta 

tovtols fiapvTepa, ofjXov pLovojs yap dv ovtojs 


their feet in place of a tail and use their legs instead 
of a tail to direct their flight. The flight of flying 
insects is slow and weak, because the growth of their 
wings is not in proportion to the weight of their body ; 
for their weight is considerable, while their wings 
are small and weak ; so they use their power of flight 
like a merchant-ship attempting to travel by means 
of oars. The weakness also of the wings themselves 
and of their manner of growth contributes to some 
extent to the result which we have described. Among 
birds, the peacock's tail is at one season of no service 
because of its size, at another useless because the 
bird moults. But birds are the exact opposite of 
winged insects in the nature of their wings, especially 
the swiftest flyers among them, namely, those with 
curved talons ; for their swiftness of flight is useful 
in enabling them to gain their livelihood. The other 
parts of their body, too, seem to be similarly adapted 
for their particular movement, the head being always 
small and the neck not thick and the breast strong and 
sharp — sharp so as to be compact like the prow of a 
light-built ship, and strong owing to the way the flesh 
grows — so as to thrust aside the air which meets it, 
and that easily and without effort ; but the hinder 
parts are light and contract again to a narrow point, 
in order that they may follow the forward parts with- 
out sweeping the air by their breadth. 

XI. So much for the discussion of these topics. 
The reason why an animal which is to walk erect 
must both be a biped and also have the upper part 
of its body lighter and the parts situated beneath 
these heavier is obvious ; for only if it were so 



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TCOV V7T07To8cOV Kal tCT^UpOTaTCl. SrjAoV 8e 7TOL€L 

tovto Kal to ovfxf3aLvov tols 7ratStots" ov yap 
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8e tt]$ rjAiKias av^7]OLV Aa^/Savec ra kcltco [xaXXov, 
\i&XP l 7T€ P & v XdficouL to TTpoarjKov fieyeOos, Kal 
TTOiovvrai tot€ tols awfjuavL TTjv pd8iGcv 6p9rjv. 
ol S* opviOes Kov<j>oL 6vt€s 8ltto81s elac 8ca to 
diriadev avTols to fidpos etvac, Kaddirep Ipyd^ovrai 


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€K tovtcov Kal otl opdov ovk eVSe^ercu TOV 
opvL0a elvaL coanep tov dvOpamov. rj yap tcov 
7TT€pcov <f>vaLs cos €X ovaL to acofjua VVV OVTCOS 
711 a avTots XPyvLpos taTLv, SpOoXs S' ovolv dxp^aros 
1 $ Kara \6yov om. PY. 



constituted would it be able to carry itself easily. 
Therefore man, the only erect animal, has legs larger 
and stronger in proportion to the upper part of his 
body than any of the other animals which have legs. 
What happens with children illustrates this : they 
cannot walk erect because they are always dwarfish 
and have the upper parts of their body too big and 
too strong in proportion to the lower parts. As they 
grow older, the lower parts increase more quickly, 
until they attain their proper size ; and it is only then 
that they can walk with their bodies erect. Birds 
are lightly built but can stand on two feet because 
their weight is at the back, just like bronze horses 
which are made by sculptors with their fore-legs 
raised in the air. The chief reason why birds can 
stand although they are bipeds is that their hip-joint 
resembles a thigh and is of such a size that they seem 
to have two thighs, one on the leg above the joint and 
the other between this and the fundament ; but it is 
not really a thigh but a hip. If it were not so large, 
a bird could not be a biped ; for then, just as in man 
and the quadrupeds, the thigh and the rest of the 
leg would be directly attached to a short hip, and so 
the whole body would tend to fall forward too much. 
But, as it is, the hip, being long, extends up to the 
middle of the belly, and so the legs form supports at 
that point and carry the whole body. It is clear too 
from this that it is impossible for a bird to stand erect 
in the way that a man stands ; for the way that birds' 
wings grow is useful to them in the position in which 
they now hold themselves, but if they stood erect, 



av r)v, wo—ep ypd^ovGL tovs epojras exovras 
—repvyag . 

"Apia yap tols elp'qpevoLs bijXov otl oi55' avBpomov 
ovV el aXXo rt tolovtov ion Tqv fiopffyqv dwarov 
eivac 7TTepojTOv ) ov fiovov otl -nXeiooL crrffielois klvtj- 

5 aerat rj TeTTapoLV evaLpov ov, dXX otl dxprjOTOS 
avrols rj tojv TJTepvyojv e'£t£ koto. <\)VGlv klvov 
fj.€voi$' rj ok ffjVGtg ovbkv iroiel Trapa <f>uGLV. 

XII. "Oti fiev ovv el fro KaptpLS rjv ev rots 
CKeXeutv rj ev tolls oj^oTrXdraLs Kal ta^tots*, ovBev 
olov 7' rjv av tojv evaipojv /cat vttottoOojv —po- 

i«- fialveiv, elprjTai rrporepov, Kal otl KapjfjLS ovk av 
p.rfievb$ -qpep^ovvTos , ort re evavrcajg 61 re 
avdpojTTot OLTTooes ovreq Kal ol opvides rrjv row 
GKeXojv ttolovvtol Kapjjjiv, en be ra reTpdnoba 
v77evavTUfj$ Kal avrols Kal rot? dvBpo'jrroLs. 01 
[lev yap dvBpojnoL tovs p.ev ppax^ovns KapLrrrovGLv 

15 enl to. KolXa, to. be GKeX'q enl to KVprov, to 6e 
reTpdrroba to. fiev npooBLa GKeX'q eVt to Kvprov, 
ra b 1 ottlgOlo errl to kolXov o/ioiojs be Kal ol 
opviBes. oltlov o' otl rj (fruGis ovbkv b'qfiLOvpyet 
fiArrjv, ujo—ep etp-qTai rrporepov, aAAa ttovto ~po$ 
to fieXrLGTOV Ik tojv evoexojievojv. ojot* eVet 


fj.eTafioXrj tolv GKeXolv, Iotojtos \xkv Ikogtov to 
fiapos ev tovtoj Igtl, klvov pevoig o* ei? to upooBev 
Set tov 77oba tov rjyovfievov rfj Beoei kov^jov elvaL ) 
cweyovg be tt}s rropelag yivop,evqs o.v8l$ ev tovtoj 
to pdpos d.77oXajifjdveLv ) brjXov oj? dvayKolov e.K 
is tov KeKafAffrBaL to GKeXog o.vBl<$ Te evBv yiveaBai, 
fievovTos tov re koto, tov TTpoojoBevra 7rdSa 
crq\xeiov Kal TTjg Kv/jp/qg. tovto be GVp.fjaiveLv djia 


as winged eupids are represented in pictures, the 
wings would ser\ e no purpose. 

At the same time it is clear from what has been 
-aid that man, or any other creature of like form, 
cannot be winged, nut only because, being red- 
blooded, he would then move at more points than 
four, but also because the possession uf wings would 
be useless to him when moving in a natural manner. 
Now nature creates nothing unnatural. 

XJL It has alreadv been stated that, if there were 
no bending in the legs or shoulders and hips none 
of the animals which are red-blooded and have feet 
could progress ; and that bending would be impos- 
sible if sumetliing were not at rest ; and that men 
and birds, being both bipeds, bend their legs in 
opposite directions : and. furthermore, that quadru- 
peds bend their pairs of legs in opposite directions 
to one another and in an opposite manner to men. 
For men bend their arms eoneavely and their legs 
con\ e\lv. but quadrupeds bend their front legs con- 
vexlv and their back legs conca\e]y : birds too do 
the latter. The reason is that nature never does 
anything without a purpose, a< has been said before, 
but creates all things with a view to the be-t that 
eircumstances allow. And so since in all creatures 
which possess bv nature the power of locomotion by 
means of their two legs, when each leg is stationary 
the weight must be upon it, but when they move 
forward, the leading leg must ha\ e no weight upon 
it, and as progression continues it is necessary to 
transfer the weight on to this leg : it is clearly essential 
that the leg after being bent should become straight 
again, the point at which the leg is thrust forward 
and the shin remaining at rest. And it is possible 



Kdl TTpO'Uvai TO la)OV els TOVfJLTT pOoOeV pL€V k^OVTOS 

rrjv KafjLTTTjv tov rjyovpievov UKeXovs hvvaTOv, els 
TOvmuQev o° ahvvarov. ovrco fiev yap Trpoeveydev- 
30 tos tov awfiaros r) eKracns tov GKeXovs k'orai, 


fjiev Trjs KajJLTrrjs ovarjs hta hvo Kivrjaeayv eyiyveT 
av r) tov 7toS6s Qecns VTrevavTioov re olvtolls, 1 kcu 
711 b Trjs p<ev els to oiriadev Trjs he els to efATTpoaBev 
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[lev firjpov to evyaTov els TOVTTicrdev TTpodyetv, 
ttjv he KvrjfjL7]v oltto Trjs Kapi7T7js els to eparpoadev 
tov iroha Kiveiv. els to ep,Trpoa6ev he Trjs KapLvrjs 

5 ovarjs, ovd* vrrevavTiais Kivr\aeai /xta Te tt} els 
to epLTTpoaQev r) XexOetaa rtopela ov\L^r\oeTai. 

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tottov fxeTafioXrjV /card <j)vaiv toIs o~KeXecri ttoiov- 
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irpoaQev tol crKeXrj, tovs he ^pa^lovas eirl to kolXov 

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^cpoTOKa tol fiev epiTTpoadev CFKeXrj, eTreihrj r)yeiTal 
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tco epurpoodev tov odjpiaTOSi dvdyKTj KapaTTeiv 

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TTpoaOev tov elprjfievov Tporrov, Kal yap ovtojs 
fxev Trjs Kapupews avTa>v yivopLevrjs eirl ttoXv 
hwrjGOVTai tovs trohas fieTecopi^eiv evavTia>s Se 

1 virevavTtuv re aureus Jaeger: bwevavTlus re (5e UZ) avrat 



for this to happen and for the animal at the same 
time to progress if the leading leg can bend forward, 
but impossible if it bends backwards. For in the 
first case the extension of the leg will take place with 
the forward movement of the body, in the second 
case with its backward movement. Further, if the 
bending were backwards, the planting of the foot 
would be carried out by two movements contrary to 
one another, one backwards and the other forwards. 
For in bending the leg it is necessary to draw the 
extremity of the thigh backwards, and the shin 
would move the foot forwards from the point of 
bending ; but if the bending be forward, the 
progression described above will take place not by 
two contrary movements but by a single forward 

Man then, being a biped and carrying out the 
change from place to place in a natural manner by 
means of his legs, bends his legs forwards for the 
reason already stated, but bends his arms concavely. 
This is only in accordance with reason ; for if they 
were bent in the opposite direction, they would be 
useless for the purpose of the hands and for taking 
food. But viviparous quadrupeds of necessity bend 
their front legs in an outward curve, because these 
legs lead the way when they walk, and are also 
situated in the front part of their bodies ; and the 
reason is the same as in man, for in this they resemble 
man. Thus the quadrupeds too bend their legs 
forward in the manner already described ; for indeed, 
since they bend their legs in this way, they will be 
able to raise their feet high in the air, whereas, if 
they bent them in the opposite direction, they would 




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en tols ye OrjAa^opievoLs avTwv Kal 7rpos tt)v 
so TOiavTTjv XeiTOvpyiav dvayKalov t) (HXtlov y* ovtw 
KeKafx^Oat rd GKeXrj' ov yap pdSiov tt)v Kapufjiv 
7TOLOvfjL€vcov ivTos v<f>* avTa e\eLV tol TeKva Kal 
o 'Ken -d^eiv . 

712 a XIII. "Ovtwv he TeTTapcov TpoTTCov Trjs Kapapews 
Kara tovs avvSvaopiovs 1 (dvdyKrj yap KapLTTTeiv 
rj errl to kolXov Kal ra TTpoodia Kal ra dir'tadta, 
Kauairep e<p ois A, 77 eni tovvovtiov €ttl to KVpTov, 
KadaTrep €</>' ois B, 7) dvTeoTpapLpiivws Kal firj eirl 
6 ra avTa, dXXa ra pcev TrpoaOta eVi to KvpTOV, ra 
S' diTLod 1a eirl to kolXov, KaBdrrep ecf>* ots to T, 

1 avvbvaafjLobs Z : crvvdicrjxovs ceteri. 



lift them only a little way from the ground, because 
the whole of the thigh and the joint from which the 
shin grows would come up against the belly as the 
animal advanced. On the other hand, if the bend- 
ing of the back legs were forward, the raising of the 
feet would be similar to that of the front feet (for 
they could only be raised a short distance by lifting 
the legs, since the thigh and the joint of both legs 
would come up under the region of the belly), but 
the bending being, as it is, backwards, there is no- 
thing to hinder their progression as they move the 
feet in this manner. Again, for those animals which 
are suckling their young, it is necessary, or at any 
rate better, that their legs should bend in this way 
with a view to this function ; for if they bent their 
legs inwards, it would not be easy for them to keep 
their young underneath them and to protect them, 

XIII. Now there are four ways of bending the legs 
taking them in pairs. Both the fore and the hind 
legs must bend either concavely, as in figure A ; or 
in the opposite manner, that is convexly, as in B : 

(Mich, supplies the figures which are lacking in the mss. In each group 
the front legs are the left pair, the hind legs the right.) 

or inversely, that is to say, not in the same direction, 
but the forelegs bend convexly and the back legs 
concavely, as in C ; or (the converse of C) with the 
convexities towards one another and the concavities 



2 a 

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20 d 8e paqpos eVJ to koIXov 8l6 Kal 6 fiev ttovs 
€ttI to kolXov, 6 Se Kapirds Trjs X €L P°$ ^ttl T ° 



elprjjjievaSy klvcltol 8e tcl dirloQLa irpos tcl 
25 rrpooOev KaTa hidyLeTpov' pctTa ydp to Sc^lov tcov 


efXTTpooOev dfia Kal irpcoTov, 8i€O7rctT0 dv rj Kal 

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tolovtov xaXerrov Se owex^j TroLeludaL tyjv fi€Ta- 
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outwards, as in D. No biped or quadruped bends its 
limbs as in figure A or B, but quadrupeds bend them 
as in C. The bendings illustrated by figure D occur 
in none of the quadrupeds except the elephant, and 
in the movement of the arms and legs by man, for 
he bends his arms concavely and his legs convcxly. 

In man the bendings of the limbs always take 
place alternately in opposite directions ; for example, 
the elbow bends concavely but the wrist convexly, 
and the shoulder again convexly. Similarly in the 
legs, the thigh bends concavely, the knee convexly, 
and the foot, on the other hand, concavely. And 
obviously the lower limbs bend in opposite directions 
to the upper ; for the origin of movement bends in 
opposite directions, the shoulder convexly and the 
thigh concavely ; therefore also the foot bends con- 
cavely and the wrist convexly. 

XIV. The bendings, then, of the legs take place 
in this manner and for the reasons stated. But the 
back legs move diagonally in relation to the front 
legs ; for after the right fore leg animals move the 
left hind leg, then the left fore leg, and after it the 
right hind leg. The reason is that, if they moved the 
fore legs at the same time and first, their progression 
would be interrupted or they would even stumble 
forward, with their hind legs as it were trailing behind. 
Further, such movement would not be walking but 
jumping ; and it is difficult to keep up a continuous 
movement from place to place by jumping. An illus- 
tration of this is that, in actual fact, horses that move 
in this manner, for example in religious processions, 
soon become tired. For this reason, then, animals do 

a i.e. prancing instead of walking. 



712 bou 1 TTOIOVVTOLI TTjV KWrjaiV* €L §€ TOIS Se^LOLS dpi- 

<j)oripois 7rpa)Tois, e£co av eylyvovTO rcov epei- 

afJLOLTOOV Kal eiTlTTTOV (XV. el S?) dvdyKTJ fX€V 7) 

kIvqoiv rj Kara Sidfierpov, fir} eVSe^Tcu S' eKelvcov 
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KCLL OV TOLS Ot^iols Tj TOIS dplOTepOlS djJL(f)OT€pOlS 

a/xa. tov avrov ok rpoirov Kal oaa irXeiovs ^X €L 
io ttoScls rerrdpcov TTOieZrai ttjv Ktvrjcnv del yap ev 
tois rerrapGL rots' e<f>e£rjs ra dirladia rrpos tcz 
k'fATTpoodev KLvetraL Kara Btdfierpov. BrjXov 8' 
€77i rots" fipaSeoos Kivovfxevois. Kal oi KapKivoi 
yap tov avrov Tpoirov Ktvovvrai' twv ttoXvttoZwv 
yap eloiv. del yap Kal ovroi Kara hidfxerpov 
15 Kivovvraty e<f) y oirep av Troiwvrai rrjv rropeiav. 
IStws yap tovto to £,a>ov TroieiTai ttjv klvtjctiv' 
fiovov yap ov KiveiTai errl to -npooOev twv £,wwv y 
aAA' errl to TrXdytov. dXX* eirel tols o/x/xacrt 
StcopiorcH to TrpoaOtov, rj <f)vais Treiroi-qKev a/co- 
XovOeiv hvvafxevovs tovs S^OaXfiovs tols kwXols' 
20 KivovvTac yap els to irXdyiov avTots, ware Tpoirov 
rivd Kal tovs KapKivovs Kiveladai hid tovt' eirl 
to epurpooBev . 

XV. Oi 8' opviBes Ta GKeXrj KaOdrrep Ta TeTpd- 
7ToSa KapLiTTOvoiv. TpoTTOv yap Tiva TrapaTrX-qaLcos 

1 oi)P: om. SYUZ. 



not move separately with their front and back legs a ; 
and, if they moved with both their right legs first, 
they would not be above their supporting limbs and 
would fall. If, then, they must necessarily move in 
one or other of these two ways or else diagonally, 
and neither of the first two ways is possible, they 
must necessarily move diagonally ; for if they move 
thus they cannot, as has been explained, suffer 
either of the above ill results. For this reason horses 
and similar animals stand at rest with their legs 
advanced diagonally and not with both right or both 
left legs advanced at the same time. And those 
animals which have more than four legs move in 
the same manner ; for in any four adjoining legs the 
back legs move diagonally with the fore legs, as can 
be plainly seen in those which move slowly. 

Crabs too move in the same fashion, for they are 
among the polypods. They, too, always move on 
the diagonal principle in whatever direction they are 
proceeding. For this animal moves in a peculiar 
manner, being the only animal to move obliquely 
and not forward. But since " forward " is determined 
in relation to the vision, nature has made the crab's 
eyes able to conform with its limbs ; for its eyes 
move obliquely, and so, for this reason, crabs too can, 
in a sense, be said to move " forward." 

XV. Birds bend their legs in the same manner as 
quadrupeds ; for in a way their nature is closely 

° i.e. do not move first the front legs together and then 
their back legs together. The ms. authority is strongly in 
favour of the omission of the negative; but 712 b 4 " one or 
other of these two ways " implies the alternative of movement 
with the front legs together and then the back legs together, 
or else with the right legs together and then the left legs 



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€7TaKoXov6otr) av vireiKovTi chepofieva Ta fiev ev 
is Tco vypto ret S* ev tco dept. Ta 8e TptoyXohvTCKa 


similar. For in birds the wings serve instead of front 
legs, and so they are bent in the same manner as the 
front legs of quadrupeds, since in the movement 
involved in progression the natural beginning of 
the change is from the wings, for their particular 
form of movement is flight. Hence, if the wings 
were taken away, no bird could stand or progress 

Further, since the bird is a biped and not erect, and 
the front parts of its body are lighter, it is either 
necessary (or at any rate more desirable), in order to 
enable it to stand, that the thigh should be placed, as 
it actually is, underneath, by which I mean growing 
towards the hinder part. But if the thigh is neces- 
sarily in this position, the bending of the leg must be 
in a concave direction, as in the back legs of quad- 
rupeds, and for the same reason as we gave in dealing 
with viviparous quadrupeds. 

Generally in birds and winged insects and creatures 
that swim in the water (all, that is to say, that progress 
in the water by means of their instrumental parts), it 
is not difficult to see that it is better that the attach- 
ment of such parts should be oblique, as in fact 
it seems actually to be in the birds and the flying 
insects. The same is also true of the fishes ; for the 
wings in birds, the fins in fishes, and the wings in 
flying insects all grow obliquely. This enables them 
to cleave the air or water with the greatest speed 
and force, and so effect their movement ; for the 
hinder parts, too, can thus follow in a forward direc- 
tion, being carried along in the yielding water or air. 

The oviparous quadrupeds which live in holes, 

1 Kai ra 6m<r6ev {xbpia Jaeger : kcl\ to BirurBtv to. (rd om. YZ) 
(j,6ptcL libri. 



tcov TeTpairobcov Kai cootokcov, oiov 01 re Kpo- 
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re Kal xeXwvai, irdvTa eK tov irXayiov irpoGire- 
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such as the crocodile, the common and the spotted 
lizard, and land and water tortoises, all have their 
legs attached obliquely and stretched out upon the 
ground ; and they bend them obliquely, since they 
are thus useful in enabling them to crawl easily into 
their holes and to sit upon and protect their eggs. 
Since their legs project, they are obliged to raise 
their whole body by drawing in their thighs and 
placing them underneath them ; and in this process 
they cannot bend them otherwise than outwards. 

XVI. It has already been said that bloodless 
animals which have legs are polypods, and none of 
them quadrupeds. Their legs, except the two 
extreme pairs, are necessarily attached obliquely 
and bend upwards and are themselves bowed some- 
what backwards ; and the reason for this is plain. 
For in all such animals the middle legs must both 
lead and follow. If, therefore, they were under- 
neath them, they would have to bend both for- 
wards and backwards — forwards because they lead, 
and backwards because they follow. But since they 
must do both these things, their legs are bowed 
and make their bends obliquely, except the extreme 
pairs, which are more in accordance with nature, 
since the first pair leads and the last pair follows. 
The number of legs is a further reason for their being 
bent in this way ; for they would thus be less likely 
to get in each other's way during movement and 
collide with one another. The reason that these 
animals are bow-legged is that they all, or most of 

1 irpoffareWovTa, (cum Mich.) Jaeger: TrpoartWovTa libri. 



etvai uavTa rj ra rrXeiGTa* ov yap olov re vifjrjXd 
etvai ra ^wvto} tov Tpoirov tovtov. 

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irohwv oca TpwyXoovTiKci' ToiavTa 8' euTiv olov 
aavpat Kal KpoKoSeiXot Kal tcl noXXd twv too- 


XVII. 'AAAa twv fjiev dXXwv flXaiuovTai ra KwXa 
oid to fiaXaKa etvat, twv Se Kapdfiwv ovtwv gkXt}- 
pooipfiwv ol rrooes elulv iirl tw veiv Kal ov tov 
fiaol^eiv X^P LV ' T ^ v ^ KapKivwv r) Kapufjis els to 

25 irXdyioVy Kal ov fiefiXatGWTai warrep tols wotokols 
twv TeTpaTToSwv Kal tols avaljiois Kal ttoXvttogi, 
oid to GKXrjpoSepjJLa elvat t<z KwXa Kal OGTpaKwSrj 
ovti ov vevGTiKw Kal TpwyXoSvTT}- TTpos rfj yfj yap 
6 ft los. Kal GTpoyyvXos oe ttjv fiop^rjv, Kal ovk 
e\wv ovpoTTvyiov wGirep 6 Kapafios' TTpos ttjv 

so vevoiv yap tols Kapdfiois xPV crL l JL01 '' ° ^' ov v * v ~ 


e^et fiovoS) oid to ttoXXovs eyeiv tovs rjyefiovas 


• 71Qb20f. 
b Viz. two pairs of front legs. 
c i.e. they walk both on dry land and in the sea. 
d The whole of the section is obscure, and the text doubtful. 



them, live in holes ; for creatures that live thus 
cannot be tall. 

Crabs are the most strangely constituted of all the 
polypods ; for they do not progress forward (except 
in the sense already mentioned a ), and they alone 
among animals have several leading legs. & The 
reason is the hardness of their feet and the fact that 
they use them not for swimming but for walking ; 
for they always go along the ground. All the 
polypods bend their legs obliquely like the quad- 
rupeds that live in holes ; lizards, for instance, and 
crocodiles and most oviparous quadrupeds are of 
this nature. The reason is that they live in holes, 
some only during the breeding season, others through- 
out their lives. 

XVII. Now the other polypods d are bow-legged 
because they are soft-skinned, but the legs of the 
spiny lobster/ which is hard-skinned, are used for 
swimming and not for walking/ The bendings of 
crabs' legs are oblique but their legs are not bowed, 
as are those of viviparous quadrupeds and bloodless 
polypods, because their legs are hard-skinned and 
testaceous, the crab not being a swimming animal 
and living in holes, for it lives on the ground. More- 
over, the crab is round in shape and does not possess 
a tail like the spiny lobster ; for the latter 's tail is 
useful for swimming, but the crab does not swim. 
And it is the only animal in which the side is like a 
hinder part, because its leading feet are numerous. 9 

* There is no single word in English for this animal, the 
Latin locusta and the French langouste. 

f And therefore are not bowed, as Mich, explains. 

9 Since the crab moves sidewise, one of its sides becomes 
as it were the back, but why it should be so for the reason 
given is obscure. 




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rjoav. opLottos 8' exovoiv ol opviOeg TpoTrov TLvd 


The reason is that it does not bend its legs forwards 
and is not bow-legged. Why it is not bow-legged 
has been already explained before, namely, because 
its skin is hard and testaceous. For this reason it 
must lead off with all its legs and obliquely — obliquely 
because its bendings are oblique, and with all its legs, 
because otherwise those which were at rest would 
impede those which were moving. 

Flat-fish swim as one-eyed men walk ; for their 
nature is distorted. Web-footed birds swim with 
their feet. They are bipeds, because they take in 
breath and respire ; they are web-footed, because 
they live in the water, for their feet being of this 
kind are of service to them in place of fins. They do 
not have their legs, as the other birds do, in the 
centre of the body, but placed rather towards the 
back ; for since they are short-legged, their legs 
being set back are useful for swimming. This class 
of bird is short-legged because nature has taken 
away from the length of their legs and added to their 
feet, and has given thickness instead of length to 
the legs and breadth to the feet ; for, being broad, 
they are more useful than if they were long, in order 
to force away the water when they are swimming. 

XVIII. It is for a good reason, too, that winged 
animals have feet, while fishes have none. The 
former live on dry land and cannot always remain up 
in the air, and so necessarily have feet ; but fishes 
live in the water, and take in water and not air. 
Their fins, then, are useful for swimming, whereas 
feet would be useless. Also, if they had both feet 
and fins, they would be bloodless. Birds in a way 

1 7r\are:s Z : Trax& PSUY. 



rots ixvvoiv. Tot? pev yap opvioiv avco at rtTepvyes 
5 etcrt, rot? oe Trrepvy ta Svo ev rep TTpaveX' /cat tois 
pikv ev tols vTTTiois ol noSes, rot? Sc ev re rot? 


TrXelaroiS' /cat ol jxev ovpoirvyiov k'xovaiv, ol 8' 

XIX. Wept 8e tojv oarpaKohippuov airoprjoeiev 
av tis ris rj Ktvrjois, /cat el firj k'xovoi 8e£to> /cat 
dpLurepoVy iroQev kivovvtoli' (fxiivovTai he kivov- 

io \ieva. r\ ojwnep dvaTrrjpov Sec nOevai tt&v to 
toiovtov yevos, /cat KLvetoOai ofxolws oiov el tls 
aTTOKoijjeie tojv vttottoSojv rd GKeArj, {t}) 1 toouep 
rj (fxjoKTj /cat rj vvKrepls' /cat yap ravra rerpaTToSa, 
/ca/ccD? 8' IotLv. rd 8' oarpaKoSeppLa Kivelrat piev, 
KLvelrai Se irapd <f>vaiv ov yap eari KcvrjTLKa, aAA' 

15 a)? p,ev pLovifia /cat TrpooTrec^VKora KLvrjTLKa, w$ he 
TTopevriKa /xoVtjaa. e'xovcn 8c <j)avXa>s /cat ol KapKLVoi 
rd 8c£ta, errel e'xovat ye. SrjXoi 8' rj XV^V' ^ €L C wl> 
yap /cat loxvporepa rj 8e^ta, ai? /3ovAofJL€vwv 8t- 
QjpLoOat tojv oe^Lwv /cat tojv apiGTepcov. 

20 Ta piev ovv rrepl tojv fxoplwv, twv t' aAAa^ /cat 
raV 7rept tt)^ iropelav tojv l^ojojv /cat Tiept uaaav 
rrjv Kara rorrov f.ieTafio\ijv , rovrov k'xet tov rporrov 
tovtojv 8e Suoptapevojv e^o/xei'oV eoTi Oeojprjaat 
rtepl ifjvxfjs- 

1 ?) addidi. 
* i.e. a second pair of fins. 

b See 77.^. 527 b35 ff., where land-snails, sea-snails, oysters 
and sea-urchins are given as examples. 
c See II. A. 498 a 31, P.A. 697 b 1 ff. 

d These words can only refer to the Dp anima, which from 
its citation in the De generations animalivm, De partibus 
animal in m 9 etc., must be regarded as an earlier work. This 



resemble fishes. For birds have their wings in the 
upper part of their bodies, fishes have two fins in 
their fore-part ; birds have feet on their under-part, 
most fishes have fins ° in their under-part and near 
their front fins ; also, birds have a tail, fishes a tail-fin. 

XIX. A question may be raised as to what is the 
movement of testaceans, 6 and where their movement 
begins if they have no right and left ; for they 
obviously do move. Must all this class be regarded 
as maimed and as moving in the same way as an 
animal with feet if one were to cut off its legs, or as 
analogous to the seal and bat, which are quadrupeds 
but malformed ? c Now the testaceans move, but 
move in a way contrary to nature. They are not 
really mobile ; but if you regard them as sedentary 
and attached by growth, you find that they are 
capable of movement ; if you regard them as pro- 
gressing, you find that they are sedentary. 

Crabs show only a feeble differentiation of right 
and left, but they do show it. It can be seen in the 
claw ; for the right claw is bigger and stronger, as 
though the left and right wished to be differentiated. 

So much for our discussion of the parts of animals 
and particularly those which have to do with progres- 
sion and all change from place to place. Now that 
these points have been settled, our next task is to 
consider soul. d 

has led some critics {e.g. Brandis) to reject the whole of this 
paragraph as a later addition. Such a paragraph, however, 
is a characteristic conclusion in Aristotle, and should not be 
rejected as a whole. It is quite possible that the words 
77epi tfi v xys are corrupt, and indeed the word ^vx^s has been 
supplied by a later hand in Z, whereas the first hand had 
Itft a blank and had written ^oj^a (sic) in the margin, which 
would be a reference to the latter part of the group of treatises 
known as the Parva Aaturalia. 

82 541 


The Index is to be regarded as supplementary to the Sum- 
mary on pages 12-18. Further references will sometimes be 
found in the notes on Terminology, pages 24-39. 

The numbers 3 to 50 refer to the pages of the Introduction. 
The numbers 39a to 97b (standing for 639a to 697b) refer 
to the pages and columns of the Berlin edition which arc 
printed at the top of each page of the Greek text. The lines 
are referred to in units of five lines ; thus 
40a 1 = 640al~640a4 
40b5 = 640b5-640b9. 
Such references include footnotes to the translation. 

f, ff = following section or sections. 
Under any heading, each entry is separated from the pre- 
ceding by a dash ( / ), unless it has the same page number. 

abdomen (abdominal cavi- 
ties) 50a 10 
a bo mas um 7 4b 15 / 7 6a 10 
abscess 67b5 
" abscession " 39 / 90a5 
Acalephae 81a35 
Aesop 63a35 
allantois 93b25 
Amia 76b20 

analogv, difference by 44b 10 
/ 45b5 

Anaxagoras 40b5 / 45a35 / 

77a5 / 87a5 
animal 53b20 / 66a35 
antelope 63al0 
ants 50b 25 / 7 8b 15 / S3a5 
Aorta 52b25/6'ib>.3 '67bl5fF 

/71bl5 / 77a5 / 78al 

ape 89b30 
appendage 70a30 
Aquinas, St Thomas 42 
Arcadia 7 3a 15 
Aristotle, " lantern " of 

art 39b 15 / 40/ 1 25 
Ascidian SOao / SlalO, 25 f 
ass 67a20 / Sbb20 

" Indian " ass 63al5 
Astaci S3b25 ff 
attributes, "essential" (or 

" inseparable") 43a25 / 

4.5b 1 

auditory passages 57a 15 

backbone 51b30 / 52a 10 / 



baekward-grazing oxen 

50a 15 
Bacon, Francis 58b 15 
barn-door fowls 57b25 
bat 97bl ff 

Batos 95b25 / 96a25 / 97a5 
beak 59b 1 ff / 

62a30ff/92bl5 /93al0f 
bear 58b 1 

beautiful, the 45a25 

bee 4Sa5 / 50b25 / 6Ia20 / 

78blOf / b2bll) / S3a5, 


beetle, see dung-beetle 
belly 55a 1 

bending 541)5 / 83b 1, 30 / 

S7b25f / 89a 10 / 93b 1 
Bergson 3 

bile 49b30. See also gall 
birds 42bl0 / 57b5, 15 / 

59b Iff / 60a25 / 7ibl5ff / 

76a30 / 91a20 / 92bl ff / 

bison 63a 10 
bivalves 79b 15 ff 
Black Sea b2a25 
bladder 70bJ5ff / 7lbl5, 25 / 


"blend " 31 / 37 / 3S / 39 / 
50b25 / 52b25, 35 / 69a 10 / 
73b30 / 86al0 

blinking 57a35, bl5f / 91a20 

blood 4 / 45b5 / 47bl (current 
of), 30 ff / 49a 15, b20 / 
50a30ff / 51a 10 / 56b 1 / 
66b25 f / 07bl5ff/ 7 Sao 

blood-vessels 47 b5 / 50a25f / 
52bo0 / 5 lb 1 /65bl0f,25 / 
66h25 ; 67bl5ff 
Great Blood-vessel o2b25 / 
66b25 J 67bl5 ff / 71bl / 

blooded animals 22 j 42b 10 / 

50b25 / 65a25 / 76bl0f / 

78a5 / S5b35 ff 
bloodless animals 22 / 23 / 

42bl0 / 50b25 / 73a30 / 

blowhole 59b 15 / 9 7a 15 ff 
boar 51al 
Bonasus (33a 10 
bone 52a 1 ff / 53b30ff / 

54a30ff / 66b 15 
Boyle, K. 45a 6 
brain 52a20 ff / 56al0ff / 

5Sbl / 73bl0 / 86a5 
breast 88al0ff 
breathing-machine 59a5 
bregma 53a35 
bronchial rubes 64a25 
bull 51al / 63a35 
buttocks S9b5 ff 

caecal appendages 7 5a 10 
caecal dilatation 75b5 
Calamarv 54a20 / 7Sb30 / 

79al5/ 85aI0ff, b!5 
camel 63a 1 / 74a30 / 76b25 / 

77a35 / 88b20 / S9a30 
Canthari 82b2o 
Carabi, caraboids 79a30f / 

83b25 ff 
Carcini 83b25 ff 
Caria 7 3a 15 
Carides 83b25 ff 
carnivorous animals 55al0 / 

61b5 / 62bl / 93a 1 / 97al 
Cartesian co-ordinates 20 
cartilage 54b25 / 55a30 
catamenia 48a30 / S9al0 
cattle-flies 61a20 
Causes 3 / 8 / 11 / 21 / 24ff / 

39bl0ff / 40b5 / 41a25 / 

46a 10 
cavities 66b20 ff 
centipede S2a5, bl 


Cephalopods 23 / 54al0 / 
78a25 ff, b25 ff / S4b5 ff 

Cercidas 73a 15 

Cestreus 75al0 / 96a5 

Cetacea 69a5 / 97al5ff 

Chalcis in Euboea 77al 

chamaeleon 92a20 

chance 40a30 / 41b20 / 45a20 

ciliary motion 84b20 

classification 1 8 / 20 / 42b5 ff / 
4obJ0 ff 

claws 62b 1 I S3b30f / 84a 15, 

cloven hoof 74a25 / and 

cockchafer S2M5 
" colliquescence " 38 / 77al0 
colon 75b5, 15 

common functions to body 

and soul 9 / 43a35 
components in isolation 45a35 
" composition " 4 / 46a 10 ff 
composition of Aristotle's 

works 10 
" concoction " 31 / 34 / 50a5 / 

51a20, b25 f 52a5 / 6Sb5/ 

70a20, 25/ 72a 1 /75al0f / 

77b25 f 
connate pneuma 59b 15 / 69a 1 
controlling part 73bl0 / 

Slbl5ff/S2bl, 25 /S6al5 
Cook, A. B. 73al5 
cooling 56a20 / 62al5 / 

6Sb35 ff / 92a20 / 96b20 
copulation 89a5, 25 
Cordylus 95b25 
couvre-feu 54a5 
crab 79a30 / 91bl5 
Crex 95a20 

crocodile 60b25 f / 90b20 / 

91al5, b5 ff 
crop 74b20 ff / 78b30 f 
crow 62b5 

Crustacea 23 / 54a 1 / 57b30 / 

78a25 ff / 83b25 ff 
cuttlefish 54a20. See also 

Cuvier 44 / S4bl5 
Cyprinoi 60b35 

Darwin 4 / 7 

deer 50bl5 / 63al0,bl0 / 64al 
/ 67a20 / 77a30 / 88b25 

deformed animals 57a20 / 
60b25 / S4bl / 95b 1 

Democritus 40b30 f / 42a25 / 

derivation of words 62b20 / 

diaphragm 70a5 / 72bl0 ff 
dichotomy IS / 42b5 ff 
differentiae 42b20 ff 
disadvantageous parts 48al5 / 

59a 15 / 63a5 / 64a5 /94a 15 
Dissections 50a30 / 66a5 / 

divers 59a5 

divine things 44b25 ff / 56a5 
" division of labour " 83a20 / 

dog 74a 1 / 75a25 / 8Sa5, bl 

Indian dog 43b5 
dog-teeth 61bl0 
dolphin 55a 15 /69a5 / 77a35 / 

96b25 / 97a 15 
duality of the body 56b30 / 

63a : 20 / 67b30 / 69bl0 ff 
dung 75b30 
dung-beetle 82b25 
dwarf-like 86b 1 ff / 89b25/ 


dynamis 29 / 30-32 / 40a20 / 
46al0, bl5 ff / 47b5 / 55bl0 

ears 57a 10 ff 
earth 51a25 



earthy matter 63b25 ff etc. 
editions of Aristotle's Be 

partibus 44-45 
Edwards, Milne 83a20 
eel 96a 1, b20 

eggs 65a35 / 84a20 / 92a 15 
*' Elements " 30 / 42a20 / 

46al0, b5 / 47al0 / 48bl0 
elephant 5Sb30ff / 61a25 / 

63a 1 / S2b30 / 8Sb5, 15 / 

9 2b 15 

embryo 51b20/55al / 65bl / 
66a20 / 71b5 / 76al5 

Empedocles 40a20, b5 / 
42al5 / 4Sa30 

Emvs 71a30 

epiglottis 64b20 ff 

epipetron 81a20 

equivalents, law of organic 

** excess and defect " (" the 
more and less ") 19 / 44a20, 
bl5 / 49a30 / 55a30 / 
61b30ff / 84a30 / 92b5 

excrement 63a 15. See 

excretory organs S9a5 ff 

eve and eyelid 57a25 ff/ 
v 91a20 

eyebrows 58b 1 ff 

eyelashes 58a 1 Off 

Fabricius 43 

fat 5 la20ff / 72al 

fear50b25 / 67a 15 f / 79a25 / 

82b25 / 92a20 
feathers 92b 10 
fibres 50b 10, 30 
fin 85bl5 / 95b25ff 
Final Cause 21 / 39bl5ff / 


fire 49a20 / 50a5 ff / 52b5 
fishes 42bl0 / 5Sal / 60bl0 ff, 

35f/62a5f /66bl0 / 75al ff/ 
76a25, b20 / 95b 1 ff 

fishing-frog 95bl0 / 96a25 

fishing-rod 93a20 

flea 83a30 

flesh 47a20/51b5 / 53bl5ff/ 

60a5 f / 68a25 ff 
fly 61a20 / 78bl5 / 82bl0 / 


fluid and solid 32 / 46al5 
flux 52b30 

fontanel, anterior 53a35 
foot 82a35ff / SoalOff / 

90a25 ff 
foreskin 57b 1 

form (and matter) 9/11 / 25 / 

40al5, b20 / 41al5 
formation (process of) 27 / 

40a 1 Off / 46a25 
funnel 79al 

gadflies 61a20 

gall and gall-bladder 5 / 

gazelle 50bl5 / 63a 10, b25 
gills 59bl5 / 96bl ff / 97al5f 
glad tits 54a20 

goat 73b30 / 74b5 / 76b35f / 

Goethe 84bl5 
good, the 39b20 / 59b30 / 

" good life " 56a5 
" goodness 11 (arete) 42a30 
goosefish 95b 10 / 96a25 
grasshopper 82a 15 f 
grease 51a25 

Great Blood-vessel, see under 

Grosseteste, Richard 41 
gut 74a 10 / 75a30f 

haematoporphyria 68b5 


haemorrhage 68b 15 
hair 5Sal5 ff 

hand 87a5 ff, bl ff / 90a30 
hare 67a20 / 69b30 / 76al5 
I Iarun-al-Rashid 40 
Harvey, William 43 / 44 
hawk 70b 1 

head 56al0ff/ 58b 1 / 86a5 ff 
hearing 56b 10 

heart 47a25 / 53b5 / 54b 10 / 
56a25 / 65al0, blOff / 
7*Oa20f / 73b 10 / 77bl / 
TSbl / S6al5 / 96bl5 

heat 53b5 / 96b 15 / and 

hepatopancreas, see mecon 

Heracleitus 45al5 

Heracleotic crabs 84a 10 

Herodotus 59a 15 

Hippocrates 30 / 31 / 37 / 
40b I 5 / 48a 1 / 50b20 / 
85b5 / S6b25 

Wistaria Animalium 46a5 / 
50a30 / 60b 1 / 74b 15 / 
S0al / S4b5 / 89a 15 / 

Ilolothuria 81al5 

Homer 73al5 

hoof 90a5 ff 

horned animals 73b30 

horns 62b20 ff 

horse 63a 1 / 66b 15 / S8b20, 

hot, the 50a5 ff 

hot and cold 41bl5 / 46al5 / 

hucklebone 51a30 / 54b20 / 

90a 1 Off 
hyaena 67a20 

" idly " (" Nature does no- 
thing idlv") 61b20 / 91bl / 
94al5 / 95bl5 

immortality 37 

" Indian ass " 63al5f 

ink 79a 1 ff / 81b25 

Insects 23 / 54a25 / 57b35 / 

59bl5 / 78blO / 82al ff 
instruments, instrumental 

parts 30 / 45bl5, 25 / 46b25 

/ 47al ff, b20 / 87a5 ff 
intelligence 48al / 50b20 / 

72a30 / S6a25 f / 87a5 
intermediate creatures 23 / 

69al0 / 81al0, blO / 

S9b30 / 97al5 ff 
" internal finality " 3 
ir.iestines 50aI5*/ 74al0 ff / 

75b 1 ff / 76blO 
irrigation 68al0 f 
ischium 95al ff 

jaws 91a25 ff 
jejunum 75b25 ff 
inints 54b 15. See also 

Kerkidas 73a 15 
Kesitreus 75a 10 / 96a5 

1 kidney 70al5, b-20 / 71a25 ff 

j kite 70b 1 

1 Ivnides 81a35 
Ktesias 63al5 

* lantern of Aristotle " S0a5 
.ard 51a20 ff, b25 / 72a5 
layrnx 64a 15 ff 
iaughter 73a 1 ff 
Lee, H. D. P. 10 
Leonardo da Vinci 65b5 
leopard 67a20 / SSao 
Lesbos 80b 1 
life 55b35 / 78bl 
limpet 79b25 / 80a20 
lion 51b35 / 55al0 / 58a30 / 
86a20 / 8Sa5, bl /89a30 



lips 59b20 

liver 66a25ff / 69b25 ff/ 
73bl5ff / 77al5, 35 f, b35 

lizard 76a25 / 91a5ff 

44 lizards " {aavpat, plaited 
tubes) 85b5 

lobster S4a30 

locust S3a30 

logos 26 f / 39b 15 / 40a30 / 
42a20 / 46b 1 / 49h25/ 
78a35 / 9obl5 _ 

Lophius piscatorius 95bl0 

lumen 71bl 

Iung64a20 f / 65a 15 / 6Sb30 ff 
lynx S9a30 

Maia 84a 10 

mammae SSalo ff 

Man 44a 1 / 45b25 / 53a25 ff / 
56a5 / 5Sal5, bl / 59b30 / 
60al0ff / 61b5 / 62bl5 / 
66b5 / 69a20, bo / 71bl / 
73a5, 25 / 76b30 / 86a25ff/ 
8Sb30 / S9b5 ff / 90a2o / 

marrow 51b20ff 

marten 67a20 

matter and form 9/35/36 
mecon 79b 10 / SOa-20 
melanin 34 
Melolontha 82b 15 
membrane 73b 1 ff/77bl5,35/ 

S2bl5 / 83b20 / 91a20 
mesentery 50a25 / 7 6b 10 / 

77b35 ff 
Methydrion 73a 15 
metre 60a5 
mice 67a20 / 76b30 
Michael Scot 40 ff / 46-47 
migrants 94a5 
milk 76al0f / 88bl 
moderation 52b 15 
Moerbeke, William of 42 

moon, full 80a30 

mouth 50al0ff / 62al5ff 

96b20 ff 
Murex 61a20 
mussel 79b25 / S3bI5 
mytis ?9a5 / Slb20ff 

nails 87b20 / 90b5 
Natural science 39a 10 / 40a 
" Natural Selection " 4 
Nature 39bl5/41a25, blOff, 

42a 15 / and passim 
Naxos 77al 

Necessity 21 / 39b20ff / 
42a 1 ff, 30 ff / 45b30 / 
46b25 / 51al5 / 63b20 / 
70a30, b20 / 72b30 / 7 7a 15 , 
b20 / 7 Sal /79a25 /82b25/ 
85bl5 / 92al / 94b5 

neck 64al0;S6a5ff/92b20ff 

Nerites 79b20 

nictitating membrane 57a30 
" non-uniform " parts 2$-30/ 

46a20, bo, 30 / 47a25 / 

55b25 ff 
nostrils 5Sb25 ff 
nutriment (" ultimate ") 

50a30 / 51 a 15 / 7Sa5, 15 
nutrition 47a25 / 50a35 

octopus 52b25 / 54a20 / 
7Sb25 / 79a5ff / S5a5.15 ff 

oesophagus 50al5 / 64a 15 ff / 
74a 10, b20 / S6a20 / 

omasum 74b 15 / 76a 10 f 
omentum 76b 10 / 77b 15 
operculum 7 9b 15 
opposites, division by 43a30 
orifice 81a25 
Oryx 63a20 
os sepiae 54a20 
Ostreae S0b20 


ostrich oSalO / 95al5 / 

" ova " SOalO If, bl ff 
ox 66b 15 / 71 bo / 88b25 


oyster 80b5, 20 / 81b 10 

Parmenides 4Sa25 
Parnassus 81a20 
parrot-fish 62a5 / 75al 
"part" 28-30 / 51b25 / 64a5 / 

passages 50al5 / 56b 15 / 

71bl, 10 ff / 78al0 
ik pen " of Calamary 54a20 
penis 89a20f 

" perfect " animals 55b30/ 

66a25 / 82a30 
philosophers, early 40b5 / 

41a5ff / 47al0 
" philosophical treatises " 


phlegm 53a 1 / 77b5 
pigeon 70bl 

plants 50a20 / 55b30 / 78 alO / 
81al5 ff / 82b30 / 83bl5 / 

Plato 30 / 42b5 / 45a35 / 
51b20 / 69al5 / 76b25 

pneuma, connate 59bl5 / 

"potentiality" 42al / 47a5 / 
49b Iff / 67b20 / 68a30 

" pounce " (of cuttlefish) 

privative terms, privation 

42b20ff / 49a 15 
proboscis 78b 10 / 79a5 / 

85a30, blO 
Protagoras 42a25 
purpose 45a20 / 51al5 / 

63b20 / 70b20 / 77al5 / 

78al5 / 92al 

Purpura 61a20 / 79bl5f 
Pyrrha, strait of SObl 
Pythagoreans 70b20 

rain 53a 1 
razor-fishes 83b 15 
" realization " 35 ff 
relative size of parts 65b5 
rennet 76a5 ff 

residue 29 / 32-34 / 47b25 / 
50a20 / 70b25 / 71a5 / 
74a 15 / 75b 10 if / 76a30 / 
77al0f, 25 / 81a30 

respiration 5 / 42a30 / 62al5 / 
64b 1 / 65a 1 5 

reticulum 74b 15 / 76a5 

Rhine 97a5 

rhinoceros 63a 15 

ribs 55al 

Rimts Sardonicus 73al0 
rot 72a30 ff 
rumen 74b 15 

rumination, ruminants 74b5 / 
75al f 

St-I I ilaire, J. Barthelemy- 44 / 

St-Hilaire, G. 84bl5 
saw-teeth 6 lb 15 / 62a5 
scales 91al5 
scallops 79b25 / 80b20 / 

Scarus 62a5 / 75al 
scorpion 83a 10 
sea-anemone 81a35 
sea -cucumber 81al5 
sea-lung 81al5 
sea-nettle 81a35 
sea-sickness 64bl0 
sea-snail 78b20 / 79b5 
sea-squirt 81al0 
sea-urchin 79b25f/ 80a Iff, 30, 

bl ff / 83M0 


seal 57a20 / 71b5 / 76b25 / 

seed 41b25 / 89a5f 
Selachia 4 / 55a20, 25, 35 / 

self-defence 55b5 / 62b25 etc. 
semen 51bl0, 20 / 89a5f 
sensation 47al ff / 48a 1 / 

50b25/51al0, bl / 53b20 / 

56a 1, 15 / 66a35 / 72b30 / 

sense, " general " 86a30 
sense-organs 47a5 / 56b25 
senses 5 6a 25 If / 86al0 
Sepia 54a20 / 78b25 / 79a5 ff / 

septum 81a30 

serpents 60b5 / 76a25, b?0 / 

90bl5ff / 91b25ff / 96a5 / 

serum 51al5 / 53al 
Shakespeare 33 / 34 
sheep 7 1 b5 / 72a25 ff / 73b30 / 

7bb35 f 
sheep-rot 72a30 ff 
sinews 66bl0 / 96b5 
Siphae 96a5 
sleep 53a 10 
smell 59b 15 
Smyraena 96a5 
snake 91al5 
Socrates 42a25 
solid and fluid 47a20, blO / 

48bl /49bl0ff 
solidification 49a30 / 51a 10 
Soul 9 /34-37 /38/41al5ff/ 

50b25 / 52b5f / 67b20 / 

72bl5 / 76b25 / 7Sbl / 

86b25 / 92a20 
sounds 60a 1 f 
speech 59b30ff / 60a20/ 

61bl5 / 64bl / 73a20 
spider-crab 84al0 

spiral shells 7 9b 10 
spit-and-lampstand 83a25 
spleen 66a25 / 69b25 ff / 

70a30 ff, b30 
sponge 81al0f 
spontaneous production 

spurs 94a 10 
starfish 81b5f 
sterility 51bl0 

sting 61al5, 25 / S2al0, b30ff 
stomach 74a5 ff / 80b25 ff / 

stone 67bl 
substratum 49al5f 
suckers 85b 10 
suet 51a20ff, b25 / 72a5 
sutures 53a35 / 58b 1 / 67a5 
sweat 68b 1 

swine 63a5 / 88b 1, 10 etc. 
symmetric, 52b35 / 86a 10 
systoichitti 70b 20 

tail 5Sa30 / 84a 1 / 89b 1 ff / 

talons 94a 15 

taste 56b35 / 60a20 / 61a5 / 

90b25 ff 
Taylor, Prof. A. E. 20 
teeth 55b5 / 6 1 a30 ff / 78b 1 5 / 


teleology 3 / 48al5 / 59al5 / 

63a 10 / 94a20 
tentacles 85b 1 f 
Testacea 23/ 54a 1 /78b 10, 20 

/ 79bl ff / 83bl ff 
testicles 95a25 / 97a 10 
text and manuscripts of De 

partibus 45 ff 
theoretical sciences 40a 
Thompson, Prof. D'Arcv 10 / 

19 / 20 / 44a20 
Tipha 96a5 


tissues 4 

toad 73b30 

Toledo 40/4-1 

tongue 59b35 ff / 78b5 ff / 

90bi20 ff 
torpedo-fish 95b5 / 96a25 f 
tortoise 54a5 / 71al5f / 

73b30 / 76a30 / 9 la 15 
touch 47 / 53b20 / 56a3o 
Transformations, theory of 

19 / 20 
translations of Aristotle's 

works 39-43 / 44-45 
transmigration 36 
troglodytes 69b5 / 84a5 
Trvgon 95b5, 25 
tube-feet 81a5 
turtle 54a5 
tusks 55b 10 

umbilical cord 93b25 

umbilicus 93b20 

" uniform " parts 28-30 / 

40b20 / 46a20, b5, 30 / 

47a25, blO 
upright posture 53a30 / 56a 10 

/ 58a20 / 62b20 / 69b5 / 

8Ga25ff / S7a5 / 89bl0ff / 

90a25 / 95a 1 ff 
ureters 7 lb 15 

vaporization 52b35 / 72bl5 
variations in " parts " 47b25 ff 

ventilation 53bl 
vermiform appendix 75al5 
vertebrae 51b30 / 54b 15 / 


Vertebrates and Inverte- 
brates 45b 10 
viper 76bl f 

viscera 47a30 / 65a25 ff / 

Vivipara 55a5, blO / 62b20 / 

73b 15 / 74a25 / 85b35 ff 

wasp 83a5 

whale 69a5 / 97ai5ff 
whelk 79bl5f / 83b 10 
windpipe 64a35 ff / S6al5 
wing (of birds) 93b 1 ff 
wing (of insects) 82bo ff 
wolf 86a20 / 88a5 
woodpecker 62b5 
wryneck 95a 20 

xanthopterine 34 

Zeus lioptosmios 73a 15 
zoological works of Aris- 
totle 8 



Note: 9Sa-99b = G9Sa-G99b 
00a-14b = ?00a-714b. 

The matter contained in lines 1-5, 5-10 etc. is treated as a 
section, and each section is referred to by the number of its 
first line : e.g. 98a 1 refers to anything contained in page 
698a lines 1-4, and 13bl0 to anything contained in page 
713b lines 10-14. 

action, the result of the prac- 
tical syllogism 01a22 ff 

active )( passive 02b 10 / 

alteration, causes of 01b 15 

animals passim 

appetite 00b 10 

arms, movement of, in run- 
ning 05al5 

athletes, use of weights in 
jumping by Ooalo 

Atlas, the fable of 99a2o, bl 

back )( front, of animals 

05a25, blO 
bat 14bl0 
bees 10a 10 
beetles lOalO 

bending, as a means of 
motion 07b5 / 0Sb20 ff / 
09b 1 ; concave and convex 
ib. 10; of legs in walking 


by man 1 la25 ff, by quad- 
rupeds ib. blO, by birds 
12b 30 

bipeds 04al0, 15 / 06a25, 
bl ff / 10b5 / 12b30 

birds 09b20 ; are bipeds 
06a25 ; standing position 
of 10b 15 ff ; compared with 
fishes 14a20 ff ; birds with 
talons the swiftest flyers 
10a25 ; web-footed birds, 

bloodless animals, progres- 
sion of 12b20 ff; struc- 
ture of ib. 30 ; can have 
more than four feet 08al5 ; 
can live though divided in 
parts 07a30 

boat, illustration from a 

bones 01b5 

Boreas 98b25 


bronze, horses in 10b20 

caterpillars, 05b25 / 09a30 
children, their difficulty in 

walking lOblO 
cockchafer 10a 10 
conger-eels 08a 1 
crabs 12b 10 / 14b 15 ; curious 

structure of 13bl0 ff 
crawling 09a5, 25 
crocodile 13a 15, bl5 
cupids, pictures of winged 


De anima, referred to 00b5 / 

Be partibtis animalium, re- 
ferred to 9 Sal 

desire, as a cause of motion 
00bl5/01al /03a5; absent 
in involuntary movements 
03b 10 

diagonal movement of the 
legs 04b 1 / 12a20, bo 

dimensions of animals 04bl5 / 

earth, immobility of the 

99a30, b5 ff 
earthworms 05b25 
eels 08al ff / 09bl0 
elbow 19al0 ; elbow-joint 

98bl / 02a25 
elephant 09a 10 / 12a 10 

feet, even number of, in all 
animals 04al5 / 08a20 ff 

fiery element 03a20 

tire, movement of 99b25 / 
00a 10 

fishes 09b30 / 13b5 ; com- 
pared with birds 14a20 ff 
flat-fish 09b 10 / Ha5 

flying 98a5, bio / 09b5 
" foot," defined 06a30 
footless animals 04al0 / 

0ob20 / 06bl ; movement 

of 07b5 / 09a25 
fore-arm 9Sbl / 02a25 
fowls, domestic 10a5 

geometrical illustrations 
98al0 / 02b25 / 03b25 

good, the, as a cause of move- 
ment 00b25 ; real )( appar- 
ent good, lb. 

hand 02a30 ff 

heart 03a 10 / 03b5, 20 

heavens, movement of the 

heron lOalO 

hips 9Sbo / 09al0 / llao; of 

birds 10b20, of man ib. 
I Historia anhnaltum, referred 

to 04b 10 
Homer, quoted (Od. viii. 20- 

22) 99b3o 
hopping 05b30 
horses, of bronze 10b20, in 

religious processions 12a30 

'* impossible," meaning of 

imagination 00b 10 /01bl5 / 

02al5 / 03bl0 ff 
inferior )( superior parts 

04b20 / 05a25 / 06b 1 ff / 


insects 09b30/10a5 ff/ 13al 
intellect 00b 10 

joints 98al5 / 02a20 / 03al0 / 
05al5 ; of elbow 98bl 

jumping 05ao, 15 / 08a20 / 



knee 9SbI 

lampreys 08al 
leeches 09a30 

left )( right 05a25, bl5 ff; 
left and right sides of 
the body, similar 02bl0 ; 
weights carried on left 
shoulder 05b30 ; why men 
step off with the left foot 

legs, the 98b5 / 10b 10 ; posi- 
tion of, in movement 
09b 15 ff ; of man, bent in 
convex direction 04al5, of 
birds, in a concave direc- 
tion ib. 20 ; four ways of 
bending the legs 12a 1 ; 
transference of weight from 
one leg to another llalO ; 
of polypods 13b25 ff; 
necessary to birds 09b20 ; 
used to direct flight 

lizards 13b 15 

lobster 13b20 ff 

man, the only erect animal 
lOblO; right-handed 06a2(h 
why a biped 04a 15 ; why 
not winged Hal ; his 
action in walking 07bl5 ; 
bends his legs in a convex 
direction 04al5 

marionettes, illustration from 

Metaphysics, referred to 

mice 98bl5 
molluscs 06a30 
moon 99bl5 

motion, movement, of the 

universe 98bl0, of the 
heavens 99al0, blO, of 
animate things OOblO, of 
inanimate things OOblO, 
of the soul OObl, of red- 
blooded footless animals 
07b5 ; various kinds of 
movement 98a5 / 05a 1 ff; 
cause of movement 00b 1 5 ff; 
where situated 02a20, b5 ff; 
origin of movement 98al5, 
bl ff / 01b30 / 06bl5; 
points at which movement 
takes place 04a 1 / 07a 1 5 ff, 
b5 ff / 09b20 ; movement 
begins on the right side 
05b30 / 06bl5; movement 
implies something at rest 
outside 99b30 / 02a25 ; 
movement of one part 
necessitates rest of another 
part 9Sal5, bl ff / 00a5; 
movement by bending 
08b20 ff / 09bl / lla5 ; 
voluntary )( involuntary 
movement 03b5 ; diagonal 
movement of the legs 
04b 1 / 12a20, b5 ; move- 
ment in jumping, running, 
and walking 05a5 ff 

mover, the prime 00b5, 
moves without being itself 
moved 98a5 / 00b35, is 
eternal 00b30 

mullet 08a 1 

nature, creates nothing with- 
out a purpose 04bl5 / 
08al0, creates nothing un- 
natural lla5 

nutrition, of plants 06b5, of 
plants and animals com- 
pared 05b5 


opposite parts of the body 
move simultaneously 02b 1 » > 

oviparous quadrupeds 04bl / 

passive )( active 02a 10 / 

peacock 10a5, 20 
Physics, reference to (258b49) 
98a 10 

plants, nutrition of06b5, lack 
movement compared 
with animals 05b5, superior 
and inferior parts of 05a25, 
bl ff 

points at which movement 

takes place 04a 1 / 07a 1 5 ff, 

b5 ff / O9b20 
poles, the 99a20 ff 
polvpods 04a 10 / 06a30, b5 / 

08b 1 / 12bl0 / 13a25, bio 
porphyrio (a bird) 10a 10 
procession, religious 12a30 
purple-fish 06a 15 
purpose 00b 10 / 01a5, in 

nature 04bl5 / OSalO 

quadrupeds 04al0 ff/06a30 / 
07bl5; bending of the leers 
of quadrupeds in walking 
llblO; oviparous quad- 
rupeds 04b 1 

ray (fish) 09b 15 

red-blooded animals lla5, 
move at four points 04a 10 / 
07al5, b5 / 09b20, cannot 
live if divided into parts 

resistance of earth, air or sea 
necessary to movement 

rest )( motion 98b5 

right )( left 05a25, bl / 
06b25 / 07a5 ; movement 
originates on the right side 
05b30/06bl5 ; right side 
superior to left 06a20, 
blO ; right limbs used in 
defence 06a5 

roots of plants 05b5 

rudder, slight movement of, 
changes direction of boat 

scolopendrae 07a30 / 08b5 
seal 14b 10 

sensation 01a35, cause of 
alteration 01bl5 ; origin 
of sensation situated in the 
centre of the body 02b20 

sense-perception, in animals 
05b 10 ; objects of 98a 10 

sexual organs 03b5, 20 

shin 98bl 

shoulder 98 bl / 09al0 / Ua5 / 

sinews 01b5 
Siphae 08a5 

snakes 05b25 / 09a25, move- 
ment of 07b20 ff, why 
footless 08a5 ff 

soul, movement of the 90b 1, 
central position of 03a35, 
as origin of movement 
02bl ff / 03al 

spine 02b20 

spirit, innate, in animals 

stromboid testaceans 06a 10, 


superior )( inferior parts 
04b 20 / 05a25 / 06b 1 ff/ 07a5 
swimming 98a5, bI5 / 09b5 
syllogism, the practical 
OlalO ff 



tail, used as a rudder lOal 
talons, birds with, the swiftest 

flyers 10a25 
testaceans 06a 10, bl / Ubo 
thighs 19al5, of birds 12b30 
Tityos 9Sb25 
tortoise 13a 15 

toy-carriage, illustration from 

trumpet-shell 06a 15 

universe, movement of the 

viviparous quadrupeds 04a20 
voluntary )( involuntary 
movement 03b5 

walking 05a5 
wasps 10a 10 
water-fowl 10a 10 
web-footed birds 14a5 
weights, used by athletes 
when jumping 05al5, 
carried on left shoulder 

v. ings 05b20 / 06a25 / 09b5, 
30 ; of birds, necessary for 
walking 09b<20, and for 
standing 10b30, serve as 
front legs 12b20; ofcupids, 
useless llal; of insects 
10al5; grow obliquely 

wrestling-school 09b 10 
wrist 02b 1 

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Pbocofius : History of thi Wabs. H. B. Dewing. 7 Vols. 
Ptoloiy : Tetbaeiblos. C/. Mavetho. 
Quest- us Smyf.vaecs. A. S. Way. Verse trans. 
Szxtus Empiricus. Rev. R. G. Bury. 4 Vols. 
Sophocles. F. Srorr. -2 \ ols. \ erse trans. 
Strabo : Geography. Horace L. Jones. 5 Vols. 
Theopkrastus : Characters. J. M. Edmonds : Herodes, 

etc, A. D. Knox. 
Thzophrastcs : Es-quiry nrro Plants. Sir Arthur Hort. 

2 Vols. 

Thucydides. C. F. Smith. 4 Vols. 
Tbyphiodorcs. Cf. Oppiav. 

Xekofho>- : Cybofaedia. Walter Miller. 2 Vols. 

XzyopKOK : Hellenica, A.vabasis, Apology, akd Sympo- 
sium. C. L. Brownson and 0. J. Todd. 3 Vols. 

Xexophok : Memorabilia avd Oecoxomicvs. E. C. Mar- 

Xes'ophok : Script a Md'oha. E. C. Marchant 



Aristotle : History of Avimals. A. L. Peck. 
pLOTiyrs. A. H. Armstrong-. 


Babbitts avd Phaedrcs. B. E. Perry. 




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